How can I check if a checkbox is checked?

Question

I am building a mobile web app with jQuery Mobile and I want to check if a checkbox is checked. Here is my code.

<script type=text/javascript>
  function validate(){
    if (remember.checked == 1){
      alert("checked") ;
    } else {
      alert("You didn't check it! Let me check it for you.")
    }
  }
</script>

<input id="remember" name="remember" type="checkbox" onclick="validate()" />

But for some reason or another it doesn't execute it.

Please help !

----EDIT----- This is what I have for the moment.

<DIV data-role="content" data-theme="g">
    <DIV class=ui-grid-g-login>
        <FORM method=post action=[$=PROBE(266)/] data-theme="C">
            <P>~DATA_ERROR~</P>
            <div id="mail" data-role="fieldcontain">
                <label for="mail">Email:*</label>       
                <input id="mail" name="mail" type="email" />
            </div>
            <div id="pass" data-role="fieldcontain">
                <label for="pass">Paswoord:*</label>        
                <input id="pass" name="pass" type="password" />
            </div>
            <div id="remember" data-role="fieldcontain">
                <label for="remember">Onthoud mij</label>       
                <input id="remember" name="remember" type="checkbox" onclick="validate()" />
            </div>
            <P><INPUT class=btn name=submit value=Login type=submit  onclick="validate()"></P>  
        </FORM>
    </DIV>
</DIV><!-- /content -->

<script type=text/javascript>
function validate(){
    var remember = document.getElementById('remember');
    if (remember.checked){
        alert("checked") ;
    }else{
        alert("You didn't check it! Let me check it for you.")
    }
}
</script>

----EDIT--

Solved it, the problem was that the fieldcontain was also named 'remember'

What is `remember` in this context: `if (remember.checked == 1){`??? — PeeHaa, Mar 27 '12 at 10:05
Later on it should remember email and password. It's for a login page — Steaphann, Mar 27 '12 at 10:14
What I am trying to say is that `remember` is `undefined` in that context. Try `console.log(remember);`. — PeeHaa, Mar 27 '12 at 10:17
Which version of HTML are you using? It's not really XHTML, is it? — Mr Lister, Mar 27 '12 at 10:24
As @Steaphann mentioned in the edit, the code did not work because there are *two* elements with same id in the html. `
` and ``. None of the answers caught this issue. — Antony, Aug 05 '20 at 08:08

score 380 · Answer 1 · edited Sep 21 '21 at 10:09

380

checked is a boolean property, so you can directly use it in an if condition

<script type="text/javascript">
    function validate() {
        if (document.getElementById('remember').checked) {
            alert("checked");
        } else {
            alert("You didn't check it! Let me check it for you.");
        }
    }
</script>

edited Sep 21 '21 at 10:09

Agostino

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answered Mar 27 '12 at 10:09

Pranav

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4

I always get the message 'You didn't check it! Let me check it for you.' – Steaphann Mar 27 '12 at 10:14
Nope its working fine for me ; i am getting both alert messages. – Pranav Mar 27 '12 at 10:19
@Steaphann Did you replace the word 'remember' with your checkbox id? ...oh, just noticed 2012 0.o ...p.s. you forgot the semi-colon after the 2nd alert statement – josh.thomson Jul 11 '14 at 12:03
..What if I don't want it to check it for me and I just want to see if it's checked or not? – Mark Kramer Feb 17 '17 at 00:18
1

@josh.thomson semi-colons are optional. – kojow7 Aug 12 '19 at 23:56

score 83 · Answer 2 · edited Jan 02 '19 at 12:08

83

Try this:

function validate() {
  var remember = document.getElementById("remember");
  if (remember.checked) {
    alert("checked");
  } else {
    alert("You didn't check it! Let me check it for you.");
  }
}

Your script doesn't know what the variable remember is. You need to get the element first using getElementById().

edited Jan 02 '19 at 12:08

Newbyte

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answered Mar 27 '12 at 10:05

clem

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1

You should also advice to strip that `== 1`. Its only working because of two errors. Actually the value is `true` or `false`, he should just using `if( remeber.checked )` – jAndy Mar 27 '12 at 10:08
I always get the message 'You didn't check it! Let me check it for you.' – Steaphann Mar 27 '12 at 10:15

score 13 · Answer 3 · edited Jul 25 '14 at 11:14

13

This should allow you to check if element with id='remember' is 'checked'

if (document.getElementById('remember').is(':checked')

edited Jul 25 '14 at 11:14

Matas Vaitkevicius

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241

answered Jul 25 '14 at 11:07

Peter

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4

`is` does not belong to the DOM element object – yves amsellem Jul 19 '15 at 15:48
19

`.is()` - is a jQuery function. `.checked` is javascript. – max kaplan Nov 02 '15 at 22:30
4

Why does this have so many upvotes? Between the missing parenthesis and the mix between vanilla and jquery. The answer is terrible It's either `$('#remember').is(':checked')` or `document.getElementById('remember').checked` but mixing will never work – Tofandel Jun 08 '21 at 18:20

score 8 · Answer 4 · edited Jun 08 '12 at 10:49

8

If you are using this form for mobile app then you may use the required attribute html5. you dont want to use any java script validation for this. It should work

<input id="remember" name="remember" type="checkbox" required="required" />

edited Jun 08 '12 at 10:49

Luke

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answered Jun 08 '12 at 10:06

shenbaga kannan

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score 8 · Answer 5 · edited Sep 24 '21 at 10:41

//HTML
<input type="checkbox" id="someID">

// JavaScript
const someCheckbox = document.getElementById('someID');

someCheckbox.addEventListener('change', e => {
  if(e.target.checked === true) {
    console.log("Checkbox is checked - boolean value: ", e.target.checked)
  }
if(e.target.checked === false) {
    console.log("Checkbox is not checked - boolean value: ", e.target.checked)
  }
});

know more

score 7 · Answer 6 · edited Mar 16 '22 at 08:00

7

use like this

<script type=text/javascript>
    function validate(){
        if (document.getElementById('remember').checked){
            alert("checked") ;
        } else {
            alert("You didn't check it! Let me check it for you.")
        }
    }
</script>

<input id="remember" name="remember" type="checkbox" onclick="validate()" />

edited Mar 16 '22 at 08:00

Douwe de Haan

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answered Mar 27 '12 at 10:06

hkutluay

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1

I always get the message 'You didn't check it! Let me check it for you.' – Steaphann Mar 27 '12 at 10:10
@user1251632 WFM too. Can you edit your question and show what you have now? Perhaps you made a copy and paste error. – Mr Lister Mar 27 '12 at 10:22
document.getElementById('remember').checked == 1 was changed by me bfore your comment.. it may be the problem. – hkutluay Mar 27 '12 at 10:31

score 6 · Answer 7 · edited Mar 16 '22 at 08:00

6

Use this below simple code: https://jsfiddle.net/Divyesh_Patel/v7a4h3kr/7/

<input type="checkbox" id="check">
<a href="#" onclick="check()">click</a>
<button onclick="check()">button</button>
<script>
  function check() {
    if (document.getElementById('check').checked) {
      alert("checked");
    } else {
      alert("Not checked.");
    }

  }
</script>

edited Mar 16 '22 at 08:00

Douwe de Haan

5,424
1
28
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answered Oct 16 '19 at 04:41

Divyesh

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score 6 · Answer 8 · edited Mar 16 '22 at 08:01

6

This should work

function validate() {
    if ($('#remeber').is(':checked')) {
        alert("checked");
    } else {
        alert("You didn't check it! Let me check it for you.");
    }
}

edited Mar 16 '22 at 08:01

Douwe de Haan

5,424
1
28
40

answered Apr 20 '20 at 11:15

Aditya

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11

Worked for me! For whatever reason, I had problems with what should be so simple. – Dumber_Texan2 Jun 20 '21 at 23:51

score 4 · Answer 9 · edited Mar 16 '22 at 08:01

4

if (document.getElementById('remember').checked) {
    alert("checked");
}
else {
    alert("You didn't check it! Let me check it for you.");
}

edited Mar 16 '22 at 08:01

Douwe de Haan

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answered May 15 '13 at 10:14

Lakshmana Kumar

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3
15
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score 4 · Answer 10 · answered Jun 13 '18 at 18:18

I am using this and it works for me with Jquery:

Jquery:

var checkbox = $('[name="remember"]');

if (checkbox.is(':checked'))
{
    console.log('The checkbox is checked');
}else
{
    console.log('The checkbox is not checked');
}

Is very simple, but work's.

Regards!

score 3 · Answer 11 · answered Mar 27 '12 at 10:07

remember is undefined … and the checked property is a boolean not a number.

function validate(){
    var remember = document.getElementById('remember');
    if (remember.checked){
        alert("checked") ;
    }else{
        alert("You didn't check it! Let me check it for you.")
    }
}

score 1 · Answer 12 · answered Apr 16 '21 at 09:22

The remember variable is undefined. so try this way:

function validate() {
  var remember = document.getElementById("remember");
  if (remember.checked) {
    alert("checked");
  } else {
    alert("You didn't check it! Let me check it for you.");
  }
}

Dhiaa Shalabi · Answer 13 · 2021-08-31T12:40:02.967

You can use this simple and effective code using pure JS and jQuery.

using validate function as onclick attr

function validate(el) {
    if (el.checked) {
        alert("checked")
    } else {
        alert("unchecked")
    }
}

<input id="remember" name="remember" type="checkbox" onclick="validate(this)" />

OR

using pure JS

document.addEventListener("DOMContentLoaded", function(event) { 
    //using pure Js code
    let chk = document.getElementById("remember");
    if (chk.checked) {
        alert("checked")
    }else{
        alert("unchecked")
    }
})

<input id="remember" name="remember" type="checkbox"/>

using jQuery

$(document).ready(function () {
    //using jQuery code
    $('#remember').on('change', function (e) {
        if (e.currentTarget.checked) {
            alert("checked")
        } else {
            alert("unchecked")
        }
    })
})

<input id="remember" name="remember" type="checkbox"/>
<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>

I recommend you to use attr `onclick` or use jQuery code. – Dhiaa Shalabi Aug 31 '21 at 12:50 — Dhiaa Shalabi, Aug 31 '21 at 12:50

score 0 · Answer 14 · edited Apr 21 '21 at 13:48

0

You can try this:

if ($('#remember').is(':checked')){
   alert('checked');
}else{
   alert('not checked')
}

edited Apr 21 '21 at 13:48

Radames E. Hernandez

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answered Oct 09 '19 at 02:45

Donminick Bautista

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4

score 0 · Answer 15 · edited Mar 16 '22 at 08:02

Use this below simple code: https://jsfiddle.net/Divyesh_Patel/v7a4h3kr/7/

<input type="checkbox" id="check">
<a href="#" onclick="check()">click</a>
<button onclick="check()">
button
</button>
<script>
  function check() {
    if (document.getElementById('check').checked) {
      alert("checked");
    } else {
      alert("You didn't check it! Let me check it for you.");
    }

  }
</script>

score -1 · Answer 16 · answered Oct 18 '13 at 07:26

Try This

<script type="text/javascript">
window.onload = function () {
    var input = document.querySelector('input[type=checkbox]');

    function check() {
        if (input.checked) {
            alert("checked");
        } else {
            alert("You didn't check it.");
        }
    }
    input.onchange = check;
    check();
}
</script>

score -2 · Answer 17 · edited May 11 '18 at 13:11

-2

You can also use JQuery methods to accomplish this:

<script type="text/javascript">
if ($('#remember')[0].checked) 
{
 alert("checked");
}
</script>

edited May 11 '18 at 13:11

Jesse

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answered May 11 '18 at 12:12

Supriya

1
1

How can I check if a checkbox is checked?

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