Question

我正在处理具有多个页面的表单。在一页上，我有复选框，要求至少在提交之前选中一个复选框。我该如何使用javascript / html5做到这一点

这是用javascript更改页面的全部一种形式。如何在最后一页上检查是否已至少选中一个复选框？请并且感谢您对高级的任何帮助！

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

* {
  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: #4CAF50;
  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: #4CAF50;
}

<form id="regForm" action="/action_page.php">
  <h1>Register:</h1>
  <!-- One "tab" for each step in the form: -->
  <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">
    <H3 id="subhead">AUDITORIUM ROOM SETUP & EQUIPMENT REQUESTS</H3>
    <label><label id="asterisk">*</label>Room Setup (Select all that apply):</label><br><br>
    <!-- <p><input placeholder="dd" oninput="this.className = ''" name="dd"></p> -->
    <br>
    <input id="element_3_1" name="Room-Setup" required type="checkbox" value="Auditorium-Seating-for-300" />
    <label class="choice" id="labelinput" for="element_3_1">Auditorium Seating for 300</label>

    <br>
    <input id="element_3_2" name="Room-Setup" class="elementcheckbox" type="checkbox" value="Auditorium-Seating-for-350" />
    <label class="choice" id="labelinput" for="element_3_2">Auditorium Seating for 350 (recommended max for Performances</label>

    <label class="choice" for="element_3_3">Auditorium Seating 400</label>
    <input id="element_3_3" name="Room-Setup" class="elementcheckbox" type="checkbox" value="Auditorium-Seating-400" />

    <label class="choice" for="element_3_4">Round Tables and Chairs</label>
    <input id="element_3_4" name="Room-Setup" class="elementcheckbox" type="checkbox" value="Round-Tables-and-Chairs" />

    <label class="choice" for="element_3_5">Other (Please note that we cannot change the auditorium setup during your event*)</label>
    <input id="element_3_5" name="Room-Setup" class="elementcheckbox" type="checkbox" value="Other" />
  </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>

Answer 1

这是一个至少验证一个复选框的页面。

<html>
<head>

<script>
	   
 var checkbox = document.querySelector("input[name=checkbox]");
function mFunction (e) 
{  
  if(![...document.querySelectorAll("input[type='checkbox']")].some(i=>i.checked))
  {
     alert('not checked');
     e.preventDefault();
  }
};
function checkForm(t,e) { 
  e.preventDefault();
  console.log('checked'); 
};
//another way to check if check box checked -check!
   //  function mFunction () {
   //  let matches = document.querySelectorAll('input[type=checkbox]:checked');
   //  if (matches.length < 1) {
   //      alert('not checked');
   //      return false;
   //  }
   // };
</script>

</head>
<body>
<!-- <form>
  <input type="checkbox" name="choice1" value="choice1" id="confirm">choice 1<br>
  <input type="checkbox" name="choice2" value="choice2" >choice 2<br>
  <input type="checkbox" name="choice3" value="choice3">choice 3<br><br>
  <input type="submit" value="Submit" onclick="mFunction()">
    
</form>
 -->
 <form onsubmit="checkForm(this,event);">
  <input type="checkbox" name="choice1" value="choice1" id="confirm">choice 1<br>
  <input type="checkbox" name="choice2" value="choice2" >choice 2<br>
  <input type="checkbox" name="choice3" value="choice3">choice 3<br><br>
  <input type="submit" value="Submit" onclick="mFunction(event)"> 
</form>

</html>

Answer 2

在验证功能中，首先检查当前选项卡是否具有任何复选框。如果是这样，请检查是否至少检查了其中之一。如果没有，请设置valid = false

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;
    }
  }
  // Are there any checkboxes on the current page?
  if (x[currentTab].querySelector("input[type=checkbox]")) {
    // Is at least one of them checked?
    if (!x[currentTab].querySelector("input[type=checkbox]:checked")) {
      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
}

如何在提交多页表单之前确保至少选中一个复选框？

2 个答案: