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@Shweta Chauhan • 22 May, 2016 • 1 like
I am trying to work out this code, but this thing is not working!
if(form.interest[0].checked==false && form.interest[1].checked==false && form.interest[2].checked==false && form.interest[3].checked==false)
alert("Please Check");
return false;
<input type="checkbox" name="interest[]" value="News"/>News
        <input type="checkbox" name="interest[]" value="Health"/>Health
        <input type="checkbox" name="interest[]" value="Automobiles"/>Automobiles
        <input type="checkbox" name="interest[]" value="Internet"/>Internet
Please guide and tell me how to do multiple checkbox validation using javascript.
@Kaustubh Katdare • 22 May, 2016 • 1 like I'd strongly using jQuery unless you've special interest in learning plain vanilla JS. That said, you should always look at the 'Console' in Chrome by inspecting your page.

I'm not well versed with JavaScript; but here's a working example of your code.

<!DOCTYPE html>
<html lang="en">
    <meta charset="UTF-8">
    <title>CheckBox Validation</title>
    <script type="text/javascript" language="JavaScript">

        function checkCheckBoxes(theForm) {

            var test = document.getElementsByName("interest[]");

            if(test[0].checked==false && test[1].checked==false && test[2].checked==false)
                alert("Please Check");
                return false;



        <form action="" onsubmit="return checkCheckBoxes(this)" name="checkForm">

            <input type="checkbox" name="interest[]" value="News"/>News
            <input type="checkbox" name="interest[]" value="Health"/>Health
            <input type="checkbox" name="interest[]" value="Automobiles"/>Automobiles

            <p><input type="SUBMIT" value="Submit!"></p>


@Anoop Kumar • 23 May, 2016 • 1 like If you really want to go with only javascript to build the foundation of scripting. Here is the code.
HTML in Body tag

<form name="fname">

        <input type="checkbox" name="interest" value="News" onclick="checkCheckBox()"/>News
        <input type="checkbox" name="interest" value="Health" onclick="checkCheckBox()"/>Health
        <input type="checkbox" name="interest" value="Automobiles" onclick="checkCheckBox()"/>Automobiles
        <input type="checkbox" name="interest" value="Internet" onclick="checkCheckBox()"/>Internet

Javascript code inside Head tag
<script type="text/javascript">
        function checkCheckBox() {
           var chk_arr = document.fname.interest;
           for(var i = 0; i < chk_arr.length; i++){
               if(chk_arr[i].checked) {
  1. You are not using document (primary node) to find the elements in page.
  2. How does javascript will be called. You need call piece of script (say a function) to execute on an event. Such as checking and unckecking of a checkbox.

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