Обход проверки формы, когда поле скрыто с помощью JQuery

var currentTab = 0; // Current tab is set to be the first tab (0)
showTab(currentTab); // Display the crurrent tab

function showTab(n) {
  // This function will display the specified tab of the form...
  var x = document.getElementsByClassName("tab");
  x[n].style.display = "block";
  //... and fix the Previous/Next buttons:
  if (n == 0) {
    document.getElementById("prevBtn").style.display = "none";
  } else {
    document.getElementById("prevBtn").style.display = "inline";
  }
  if (n == (x.length - 1)) {
    document.getElementById("nextBtn").innerHTML = "Submit";
  } else {
    document.getElementById("nextBtn").innerHTML = "Next";
  }
  //... and run a function that will display the correct step indicator:
  fixStepIndicator(n)
}

function nextPrev(n) {
  // This function will figure out which tab to display
  var x = document.getElementsByClassName("tab");
  // Exit the function if any field in the current tab is invalid:
  if (n == 1 && !validateForm()) return false;
  // Hide the current tab:
  x[currentTab].style.display = "none";
  // Increase or decrease the current tab by 1:
  currentTab = currentTab + n;
  // if you have reached the end of the form...
  if (currentTab >= x.length) {
    // ... the form gets submitted:
    document.getElementById("regForm").submit();
    return false;
  }
  // Otherwise, display the correct tab:
  showTab(currentTab);
}

function validateForm() {
  // This function deals with validation of the form fields
  var x, y, i, valid = true;
  x = document.getElementsByClassName("tab");
  y = x[currentTab].getElementsByTagName("input");
  // A loop that checks every input field in the current tab:
  for (i = 0; i < y.length; i++) {
    // If a field is empty...
    if (y[i].value == "") {
      // add an "invalid" class to the field:
      y[i].className += " invalid";
      // and set the current valid status to false
      //valid = false;
      (y[i].style.display == "none")?valid = true:valid = false;
    }
  }
  // If the valid status is true, mark the step as finished and valid:
  if (valid) {
    document.getElementsByClassName("step")[currentTab].className += " finish";
  }
  return valid; // return the valid status
}

function fixStepIndicator(n) {
  // This function removes the "active" class of all steps...
  var i, x = document.getElementsByClassName("step");
  for (i = 0; i < x.length; i++) {
    x[i].className = x[i].className.replace(" active", "");
  }
  //... and adds the "active" class on the current step:
  x[n].className += " active";
}
	$("input[type='radio']").change(function(){
   
if ($(this).val()= = "true")
{
    $("#otherAnswer").show();
}
else
{
       $("#otherAnswer").hide(); 
}
    
});

* {
  box-sizing: border-box;
}

body {
  background-color: #f1f1f1;
}

#regForm {
  background-color: #ffffff;
  margin: 100px auto;
  font-family: Raleway;
  padding: 40px;
  width: 70%;
  min-width: 300px;
}

h1 {
  text-align: center;  
}

input {
  padding: 10px;
  width: 100%;
  font-size: 17px;
  font-family: Raleway;
  border: 1px solid #aaaaaa;
}

/* Mark input boxes that gets an error on validation: */
input.invalid {
  background-color: #ffdddd;
}

/* Hide all steps by default: */
.tab {
  display: none;
}

button {
  background-color:  #bda576;
  color: #ffffff;
  border: none;
  padding: 10px 20px;
  font-size: 17px;
  font-family: Raleway;
  cursor: pointer;
}

button:hover {
  opacity: 0.8;
}

#prevBtn {
  background-color: #bbbbbb;
}

/* Make circles that indicate the steps of the form: */
.step {
  height: 15px;
  width: 15px;
  margin: 0 2px;
  background-color: #bbbbbb;
  border: none;  
  border-radius: 50%;
  display: inline-block;
  opacity: 0.5;
}

.step.active {
  opacity: 1;
}

/* Mark the steps that are finished and valid: */
.step.finish {
  background-color:  #bda576;
}
	
	/* Checkbox code */
	/* Customize the label (the container) */
.container {
  display: block;
  position: relative;
  padding-left: 35px;
  margin-bottom: 12px;
  cursor: pointer;
  font-size: 22px;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

/* Hide the browser's default checkbox */
.container input {
  position: absolute;
  opacity: 0;
  cursor: pointer;
  height: 0;
  width: 0;
}

/* Create a custom checkbox */
.checkmark {
  position: absolute;
  top: 0;
  left: 0;
  height: 25px;
  width: 25px;
  background-color: #eee;
}

/* On mouse-over, add a grey background color */
.container:hover input ~ .checkmark {
  background-color: #ccc;
}

/* When the checkbox is checked, add a blue background */
.container input:checked ~ .checkmark {
  background-color: #2196F3;
}

/* Create the checkmark/indicator (hidden when not checked) */
.checkmark:after {
  content: "";
  position: absolute;
  display: none;
}

/* Show the checkmark when checked */
.container input:checked ~ .checkmark:after {
  display: block;
}

/* Style the checkmark/indicator */
.container .checkmark:after {
  left: 9px;
  top: 5px;
  width: 5px;
  height: 10px;
  border: solid white;
  border-width: 0 3px 3px 0;
  -webkit-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  transform: rotate(45deg);
}
	/* The container */
.container {
    display: block;
    position: relative;
    padding-left: 35px;
    margin-bottom: 12px;
    cursor: pointer;
    font-size: 22px;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

/* Hide the browser's default checkbox */
.container input {
    position: absolute;
    opacity: 0;
    cursor: pointer;
    height: 0;
    width: 0;
}

/* Create a custom checkbox */
.checkmark {
    position: absolute;
    top: 0;
    left: 0;
    height: 25px;
    width: 25px;
    background-color: #eee;
}

/* On mouse-over, add a grey background color */
.container:hover input ~ .checkmark {
    background-color: #ccc;
}

/* When the checkbox is checked, add a blue background */
.container input:checked ~ .checkmark {
    background-color:  #bda576;
}

/* Create the checkmark/indicator (hidden when not checked) */
.checkmark:after {
    content: "";
    position: absolute;
    display: none;
}

/* Show the checkmark when checked */
.container input:checked ~ .checkmark:after {
    display: block;
}

/* Style the checkmark/indicator */
.container .checkmark:after {
    left: 9px;
    top: 5px;
    width: 5px;
    height: 10px;
    border: solid white;
    border-width: 0 3px 3px 0;
    -webkit-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    transform: rotate(45deg);
}

<!DOCTYPE html>
<html>
<meta name = "viewport" content = "width=device-width, initial-scale=1.0">
<link href = "https://fonts.googleapis.com/css?family=Raleway" rel = "stylesheet">
<script src = "https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<body>

<form id = "regForm" action = "/action_page.php">
  <h1>Register:</h1>
  <!-- One "tab" for each step in the form: -->
	<div class = "tab"> 
		<label class = "container">No
  <input type = "radio" checked = "checked" value = "false" name = "radio">
  <span class = "checkmark"></span>
</label>
		<label class = "container">Yes
  <input type = "radio" value = "true" name = "radio">
  <span class = "checkmark"></span>
</label>
<input style = "display:none;" type = "text" name = "otherAnswer" id = "otherAnswer"/>
</div>
	
  <div class = "tab">Name:
    <p><input placeholder = "First name..." oninput = "this.className = ''" name = "fname"></p>
    <p><input placeholder = "Last name..." oninput = "this.className = ''" name = "lname"></p>
  </div>
  <div class = "tab">Contact Info:
    <p><input placeholder = "E-mail..." oninput = "this.className = ''" name = "email"></p>
    <p><input placeholder = "Phone..." oninput = "this.className = ''" name = "phone"></p>
  </div>
  <div class = "tab">Birthday:
    <p><input placeholder = "dd" oninput = "this.className = ''" name = "dd"></p>
    <p><input placeholder = "mm" oninput = "this.className = ''" name = "nn"></p>
    <p><input placeholder = "yyyy" oninput = "this.className = ''" name = "yyyy"></p>
  </div>
  <div class = "tab">Login Info:
    <p><input placeholder = "Username..." oninput = "this.className = ''" name = "uname"></p>
    <p><input placeholder = "Password..." oninput = "this.className = ''" name = "pword" type = "password"></p>
  </div>
  <div style = "overflow:auto;">
    <div style = "float:right;">
      <button type = "button" id = "prevBtn" onclick = "nextPrev(-1)">Previous</button>
      <button type = "button" id = "nextBtn" onclick = "nextPrev(1)">Next</button>
    </div>
  </div>
  <!-- Circles which indicates the steps of the form: -->
  <div style = "text-align:center;margin-top:40px;">
    <span class = "step"></span>
    <span class = "step"></span>
    <span class = "step"></span>
    <span class = "step"></span>
  </div>
</form>
</body>
</html>

var currentTab = 0; // Current tab is set to be the first tab (0)
showTab(currentTab); // Display the crurrent tab

function showTab(n) {
  // This function will display the specified tab of the form...
  var x = document.getElementsByClassName("tab");
  x[n].style.display = "block";
  //... and fix the Previous/Next buttons:
  if (n == 0) {
    document.getElementById("prevBtn").style.display = "none";
  } else {
    document.getElementById("prevBtn").style.display = "inline";
  }
  if (n == (x.length - 1)) {
    document.getElementById("nextBtn").innerHTML = "Submit";
  } else {
    document.getElementById("nextBtn").innerHTML = "Next";
  }
  //... and run a function that will display the correct step indicator:
  fixStepIndicator(n)
}

function nextPrev(n) {
  // This function will figure out which tab to display
  var x = document.getElementsByClassName("tab");
  // Exit the function if any field in the current tab is invalid:
  if (n == 1 && !validateForm()) return false;
  // Hide the current tab:
  x[currentTab].style.display = "none";
  // Increase or decrease the current tab by 1:
  currentTab = currentTab + n;
  // if you have reached the end of the form...
  if (currentTab >= x.length) {
    // ... the form gets submitted:
    document.getElementById("regForm").submit();
    return false;
  }
  // Otherwise, display the correct tab:
  showTab(currentTab);
}

// Where el is the DOM element you'd like to test for visibility
*function isHidden(el) {
    var style = window.getComputedStyle(el);
    return (style.display === 'none')
}*

function validateForm() {

  // This function deals with validation of the form fields
  var x, y, i, valid = true;
  x = document.getElementsByClassName("tab");
  y = x[currentTab].getElementsByTagName("input");
  // A loop that checks every input field in the current tab:
  for (i = 0; i < y.length; i++) {
    // If a field is empty...
    if (y[i].value == "" && !isHidden(y[i])) {
      // add an "invalid" class to the field:
      y[i].className += " invalid";
      // and set the current valid status to false
      valid = false;
    }
  }
  // If the valid status is true, mark the step as finished and valid:
  if (valid) {
    document.getElementsByClassName("step")[currentTab].className += " finish";
  }
  return valid; // return the valid status
}

function fixStepIndicator(n) {
  // This function removes the "active" class of all steps...
  var i, x = document.getElementsByClassName("step");
  for (i = 0; i < x.length; i++) {
    x[i].className = x[i].className.replace(" active", "");
  }
  //... and adds the "active" class on the current step:
  x[n].className += " active";
}
	$("input[type='radio']").change(function(){
   
if ($(this).val()= = "true")
{
    $("#otherAnswer").show();
}
else
{
       $("#otherAnswer").hide(); 
}
    
});

<!DOCTYPE html>
<html>
<meta name = "viewport" content = "width=device-width, initial-scale=1.0">
<link href = "https://fonts.googleapis.com/css?family=Raleway" rel = "stylesheet">
<script src = "https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<style>
* {
  box-sizing: border-box;
}

body {
  background-color: #f1f1f1;
}

#regForm {
  background-color: #ffffff;
  margin: 100px auto;
  font-family: Raleway;
  padding: 40px;
  width: 70%;
  min-width: 300px;
}

h1 {
  text-align: center;  
}

input {
  padding: 10px;
  width: 100%;
  font-size: 17px;
  font-family: Raleway;
  border: 1px solid #aaaaaa;
}

/* Mark input boxes that gets an error on validation: */
input.invalid {
  background-color: #ffdddd;
}

/* Hide all steps by default: */
.tab {
  display: none;
}

button {
  background-color:  #bda576;
  color: #ffffff;
  border: none;
  padding: 10px 20px;
  font-size: 17px;
  font-family: Raleway;
  cursor: pointer;
}

button:hover {
  opacity: 0.8;
}

#prevBtn {
  background-color: #bbbbbb;
}

/* Make circles that indicate the steps of the form: */
.step {
  height: 15px;
  width: 15px;
  margin: 0 2px;
  background-color: #bbbbbb;
  border: none;  
  border-radius: 50%;
  display: inline-block;
  opacity: 0.5;
}

.step.active {
  opacity: 1;
}

/* Mark the steps that are finished and valid: */
.step.finish {
  background-color:  #bda576;
}
	
	/* Checkbox code */
	/* Customize the label (the container) */
.container {
  display: block;
  position: relative;
  padding-left: 35px;
  margin-bottom: 12px;
  cursor: pointer;
  font-size: 22px;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

/* Hide the browser's default checkbox */
.container input {
  position: absolute;
  opacity: 0;
  cursor: pointer;
  height: 0;
  width: 0;
}

/* Create a custom checkbox */
.checkmark {
  position: absolute;
  top: 0;
  left: 0;
  height: 25px;
  width: 25px;
  background-color: #eee;
}

/* On mouse-over, add a grey background color */
.container:hover input ~ .checkmark {
  background-color: #ccc;
}

/* When the checkbox is checked, add a blue background */
.container input:checked ~ .checkmark {
  background-color: #2196F3;
}

/* Create the checkmark/indicator (hidden when not checked) */
.checkmark:after {
  content: "";
  position: absolute;
  display: none;
}

/* Show the checkmark when checked */
.container input:checked ~ .checkmark:after {
  display: block;
}

/* Style the checkmark/indicator */
.container .checkmark:after {
  left: 9px;
  top: 5px;
  width: 5px;
  height: 10px;
  border: solid white;
  border-width: 0 3px 3px 0;
  -webkit-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  transform: rotate(45deg);
}
	/* The container */
.container {
    display: block;
    position: relative;
    padding-left: 35px;
    margin-bottom: 12px;
    cursor: pointer;
    font-size: 22px;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

/* Hide the browser's default checkbox */
.container input {
    position: absolute;
    opacity: 0;
    cursor: pointer;
    height: 0;
    width: 0;
}

/* Create a custom checkbox */
.checkmark {
    position: absolute;
    top: 0;
    left: 0;
    height: 25px;
    width: 25px;
    background-color: #eee;
}

/* On mouse-over, add a grey background color */
.container:hover input ~ .checkmark {
    background-color: #ccc;
}

/* When the checkbox is checked, add a blue background */
.container input:checked ~ .checkmark {
    background-color:  #bda576;
}

/* Create the checkmark/indicator (hidden when not checked) */
.checkmark:after {
    content: "";
    position: absolute;
    display: none;
}

/* Show the checkmark when checked */
.container input:checked ~ .checkmark:after {
    display: block;
}

/* Style the checkmark/indicator */
.container .checkmark:after {
    left: 9px;
    top: 5px;
    width: 5px;
    height: 10px;
    border: solid white;
    border-width: 0 3px 3px 0;
    -webkit-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    transform: rotate(45deg);
}
</style>
<body>

<form id = "regForm" action = "/action_page.php">
  <h1>Register:</h1>
  <!-- One "tab" for each step in the form: -->
	<div class = "tab"> 
		<label class = "container">No
  <input type = "radio" checked = "checked" value = "false" name = "radio">
  <span class = "checkmark"></span>
</label>
		<label class = "container">Yes
  <input type = "radio" value = "true" name = "radio">
  <span class = "checkmark"></span>
</label>
<input style = "display:none;" type = "text" name = "otherAnswer" id = "otherAnswer"/>
</div>
	
  <div class = "tab">Name:
    <p><input placeholder = "First name..." oninput = "this.className = ''" name = "fname"></p>
    <p><input placeholder = "Last name..." oninput = "this.className = ''" name = "lname"></p>
  </div>
  <div class = "tab">Contact Info:
    <p><input placeholder = "E-mail..." oninput = "this.className = ''" name = "email"></p>
    <p><input placeholder = "Phone..." oninput = "this.className = ''" name = "phone"></p>
  </div>
  <div class = "tab">Birthday:
    <p><input placeholder = "dd" oninput = "this.className = ''" name = "dd"></p>
    <p><input placeholder = "mm" oninput = "this.className = ''" name = "nn"></p>
    <p><input placeholder = "yyyy" oninput = "this.className = ''" name = "yyyy"></p>
  </div>
  <div class = "tab">Login Info:
    <p><input placeholder = "Username..." oninput = "this.className = ''" name = "uname"></p>
    <p><input placeholder = "Password..." oninput = "this.className = ''" name = "pword" type = "password"></p>
  </div>
  <div style = "overflow:auto;">
    <div style = "float:right;">
      <button type = "button" id = "prevBtn" onclick = "nextPrev(-1)">Previous</button>
      <button type = "button" id = "nextBtn" onclick = "nextPrev(1)">Next</button>
    </div>
  </div>
  <!-- Circles which indicates the steps of the form: -->
  <div style = "text-align:center;margin-top:40px;">
    <span class = "step"></span>
    <span class = "step"></span>
    <span class = "step"></span>
    <span class = "step"></span>
  </div>
</form>



</body>
</html>

    var currentTab = 0; // Current tab is set to be the first tab (0)
    showTab(currentTab); // Display the crurrent tab

    function showTab(n) {
        // This function will display the specified tab of the form...
        var x = document.getElementsByClassName("tab");
        x[n].style.display = "block";
        //... and fix the Previous/Next buttons:
        if (n == 0) {
            document.getElementById("prevBtn").style.display = "none";
        } else {
            document.getElementById("prevBtn").style.display = "inline";
        }
        if (n == (x.length - 1)) {
            document.getElementById("nextBtn").innerHTML = "Submit";
        } else {
            document.getElementById("nextBtn").innerHTML = "Next";
        }
        //... and run a function that will display the correct step indicator:
        fixStepIndicator(n)
    }

    function nextPrev(n) {
        // This function will figure out which tab to display
        var x = document.getElementsByClassName("tab");
        // Exit the function if any field in the current tab is invalid:
        if (n == 1 && !validateForm()) return false;
        // Hide the current tab:
        x[currentTab].style.display = "none";
        // Increase or decrease the current tab by 1:
        currentTab = currentTab + n;
        // if you have reached the end of the form...
        if (currentTab >= x.length) {
            // ... the form gets submitted:
            document.getElementById("regForm").submit();
            return false;
        }
        // Otherwise, display the correct tab:
        showTab(currentTab);
    }

  function checkHiddenOrNot(el) {
    var style = window.getComputedStyle(el);
    return (style.display === 'none')
  }

    function validateForm() {
        // This function deals with validation of the form fields
        var x, y, i, valid = true;
        x = document.getElementsByClassName("tab");
        y = x[currentTab].getElementsByTagName("input");
        // A loop that checks every input field in the current tab:
        for (i = 0; i < y.length; i++) {
            // If a field is empty...
            var inputForNoChecked = $('#noRadio').is(':checked');
            if (y[i].value == "" && !checkHiddenOrNot(y[i])) {
                // add an "invalid" class to the field:
                y[i].className += " invalid";
                // and set the current valid status to false
                valid = false;
            }
        }
        // If the valid status is true, mark the step as finished and valid:
        if (valid) {
            document.getElementsByClassName("step")[currentTab].className += " finish";
        }
        return valid; // return the valid status
    }

    function fixStepIndicator(n) {
        // This function removes the "active" class of all steps...
        var i, x = document.getElementsByClassName("step");
        for (i = 0; i < x.length; i++) {
            x[i].className = x[i].className.replace(" active", "");
        }
        //... and adds the "active" class on the current step:
        x[n].className += " active";
    }
    $("input[type='radio']").change(function() {

        if ($(this).val() == "true") {
            $("#otherAnswer").show();
        } else {
            $("#otherAnswer").hide();
        }

    });

    <!DOCTYPE html>
    <html>
    <meta name = "viewport" content = "width=device-width, initial-scale=1.0">
    <link href = "https://fonts.googleapis.com/css?family=Raleway" rel = "stylesheet">
    <script src = "https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

    <style>
    * {
      box-sizing: border-box;
    }

    body {
      background-color: #f1f1f1;
    }

    #regForm {
      background-color: #ffffff;
      margin: 100px auto;
      font-family: Raleway;
      padding: 40px;
      width: 70%;
      min-width: 300px;
    }

    h1 {
      text-align: center;  
    }

    input {
      padding: 10px;
      width: 100%;
      font-size: 17px;
      font-family: Raleway;
      border: 1px solid #aaaaaa;
    }

    /* Mark input boxes that gets an error on validation: */
    input.invalid {
      background-color: #ffdddd;
    }

    /* Hide all steps by default: */
    .tab {
      display: none;
    }

    button {
      background-color:  #bda576;
      color: #ffffff;
      border: none;
      padding: 10px 20px;
      font-size: 17px;
      font-family: Raleway;
      cursor: pointer;
    }

    button:hover {
      opacity: 0.8;
    }

    #prevBtn {
      background-color: #bbbbbb;
    }

    /* Make circles that indicate the steps of the form: */
    .step {
      height: 15px;
      width: 15px;
      margin: 0 2px;
      background-color: #bbbbbb;
      border: none;  
      border-radius: 50%;
      display: inline-block;
      opacity: 0.5;
    }

    .step.active {
      opacity: 1;
    }

    /* Mark the steps that are finished and valid: */
    .step.finish {
      background-color:  #bda576;
    }
    	
    	/* Checkbox code */
    	/* Customize the label (the container) */
    .container {
      display: block;
      position: relative;
      padding-left: 35px;
      margin-bottom: 12px;
      cursor: pointer;
      font-size: 22px;
      -webkit-user-select: none;
      -moz-user-select: none;
      -ms-user-select: none;
      user-select: none;
    }

    /* Hide the browser's default checkbox */
    .container input {
      position: absolute;
      opacity: 0;
      cursor: pointer;
      height: 0;
      width: 0;
    }

    /* Create a custom checkbox */
    .checkmark {
      position: absolute;
      top: 0;
      left: 0;
      height: 25px;
      width: 25px;
      background-color: #eee;
    }

    /* On mouse-over, add a grey background color */
    .container:hover input ~ .checkmark {
      background-color: #ccc;
    }

    /* When the checkbox is checked, add a blue background */
    .container input:checked ~ .checkmark {
      background-color: #2196F3;
    }

    /* Create the checkmark/indicator (hidden when not checked) */
    .checkmark:after {
      content: "";
      position: absolute;
      display: none;
    }

    /* Show the checkmark when checked */
    .container input:checked ~ .checkmark:after {
      display: block;
    }

    /* Style the checkmark/indicator */
    .container .checkmark:after {
      left: 9px;
      top: 5px;
      width: 5px;
      height: 10px;
      border: solid white;
      border-width: 0 3px 3px 0;
      -webkit-transform: rotate(45deg);
      -ms-transform: rotate(45deg);
      transform: rotate(45deg);
    }
    	/* The container */
    .container {
        display: block;
        position: relative;
        padding-left: 35px;
        margin-bottom: 12px;
        cursor: pointer;
        font-size: 22px;
        -webkit-user-select: none;
        -moz-user-select: none;
        -ms-user-select: none;
        user-select: none;
    }

    /* Hide the browser's default checkbox */
    .container input {
        position: absolute;
        opacity: 0;
        cursor: pointer;
        height: 0;
        width: 0;
    }

    /* Create a custom checkbox */
    .checkmark {
        position: absolute;
        top: 0;
        left: 0;
        height: 25px;
        width: 25px;
        background-color: #eee;
    }

    /* On mouse-over, add a grey background color */
    .container:hover input ~ .checkmark {
        background-color: #ccc;
    }

    /* When the checkbox is checked, add a blue background */
    .container input:checked ~ .checkmark {
        background-color:  #bda576;
    }

    /* Create the checkmark/indicator (hidden when not checked) */
    .checkmark:after {
        content: "";
        position: absolute;
        display: none;
    }

    /* Show the checkmark when checked */
    .container input:checked ~ .checkmark:after {
        display: block;
    }

    /* Style the checkmark/indicator */
    .container .checkmark:after {
        left: 9px;
        top: 5px;
        width: 5px;
        height: 10px;
        border: solid white;
        border-width: 0 3px 3px 0;
        -webkit-transform: rotate(45deg);
        -ms-transform: rotate(45deg);
        transform: rotate(45deg);
    }
    </style>
    <body>

    <form id = "regForm" action = "/action_page.php">
      <h1>Register:</h1>
      <!-- One "tab" for each step in the form: -->
    	<div class = "tab"> 
    		<label class = "container">No
      <input type = "radio" checked = "checked" value = "false" name = "radio">
      <span class = "checkmark"></span>
    </label>
    		<label class = "container">Yes
      <input type = "radio" value = "true" name = "radio">
      <span class = "checkmark"></span>
    </label>
    <input style = "display:none;" type = "text" name = "otherAnswer" id = "otherAnswer"/>
    </div>
    	
      <div class = "tab">Name:
        <p><input placeholder = "First name..." oninput = "this.className = ''" name = "fname"></p>
        <p><input placeholder = "Last name..." oninput = "this.className = ''" name = "lname"></p>
      </div>
      <div class = "tab">Contact Info:
        <p><input placeholder = "E-mail..." oninput = "this.className = ''" name = "email"></p>
        <p><input placeholder = "Phone..." oninput = "this.className = ''" name = "phone"></p>
      </div>
      <div class = "tab">Birthday:
        <p><input placeholder = "dd" oninput = "this.className = ''" name = "dd"></p>
        <p><input placeholder = "mm" oninput = "this.className = ''" name = "nn"></p>
        <p><input placeholder = "yyyy" oninput = "this.className = ''" name = "yyyy"></p>
      </div>
      <div class = "tab">Login Info:
        <p><input placeholder = "Username..." oninput = "this.className = ''" name = "uname"></p>
        <p><input placeholder = "Password..." oninput = "this.className = ''" name = "pword" type = "password"></p>
      </div>
      <div style = "overflow:auto;">
        <div style = "float:right;">
          <button type = "button" id = "prevBtn" onclick = "nextPrev(-1)">Previous</button>
          <button type = "button" id = "nextBtn" onclick = "nextPrev(1)">Next</button>
        </div>
      </div>
      <!-- Circles which indicates the steps of the form: -->
      <div style = "text-align:center;margin-top:40px;">
        <span class = "step"></span>
        <span class = "step"></span>
        <span class = "step"></span>
        <span class = "step"></span>
      </div>
    </form>



    </body>
    </html>