Validating checkboxes using javascript in php

Question

I am trying to validate checkboxes in a form.

my form is as follows:

<form name="results" action=request_job.php method="post" 
onsubmit="return validateForm.apply(this)">
<td name='checkb'colspan='2' class="noborder" width='100%' align="center">
                <input type='checkbox' name='ModelArray[]' value='1'>m1
                                    <input type='checkbox' name='ModelArray[]' value='2'>m2
                                    <input type='checkbox' name='ModelArray[]' value='3'>m3
                                    <input type='checkbox' name='ModelArray[]' value='4'>m4
                                    <input type='checkbox' name='ModelArray[]' value='5'>m5
                                    <input type='checkbox' name='ModelArray[]' value='6'>m6
                                    <input type='checkbox' name='ModelArray[]' value='7'>m7

I want to there to be an alert if there is no checkboxes selected. How do i do this. I have being trying a long time now.

Thanks

solved with this:

var wrap=doc.get("checkb");
ArrCB=wrap.getelementbyTagName('input');
ArrCB_l=ArrCB.lenght();
while(ArrCB_l--){
  var CB=ArrCB[ArrCB_l];
  CB.checked()==True;
return 1
}
return 0

}

if ($('checkb :checkbox:checked').length == 0) { alert("You must answer at least one question"); } .. i names the td:checkb return true; — user1338194, May 03 '12 at 15:08
this is the last thing i have tried. I deleted the rest as they didn't work. — user1338194, May 03 '12 at 15:09
I tried looping through them as an array and i think this is what i have to do but dont no how. — user1338194, May 03 '12 at 15:10
you can cheek this issue .... http://stackoverflow.com/questions/590018/getting-all-selected-checkboxes-in-an-array — Sameh Serag, May 03 '12 at 15:14

score 2 · Answer 1 · answered May 03 '12 at 15:20

You can try this (not dependent on jQuery since you did not specify):

(function() {
    window.validateForm = {};
    window.validateForm.apply = function(o) {
        var inputs = document.getElementsByTagName("input");

        for(var i = 0; i < inputs.length; i++) {
            if(inputs[i].type == "checkbox" && inputs[i].checked) 
                return true;
        }
        alert('You must select at least 1');
        return false;
    };
})();

This will iterate over all inputs in your page. It will return true once it finds a single checked checkbox, or false if it finds none.

I added the window.validateForm = {} just so that it would work, you probably won't need that if you already have the object defined.

score 1 · Answer 2 · answered May 03 '12 at 15:21

From whatever information I could gather from your query, I have posted a solution. See if this works for you.

<form name="results" action="request_job.php" method="post" onsubmit="return validateForm()">
    <input type='checkbox' name='ModelArray[]' value='1'>m1
    <input type='checkbox' name='ModelArray[]' value='2'>m2
    <input type='checkbox' name='ModelArray[]' value='3'>m3
    <input type='checkbox' name='ModelArray[]' value='4'>m4
    <input type='checkbox' name='ModelArray[]' value='5'>m5
    <input type='checkbox' name='ModelArray[]' value='6'>m6
    <input type='checkbox' name='ModelArray[]' value='7'>m7
    <input type="submit" value="Submit">
</form>

<script type="text/javascript">
function validateForm()
{
    if( $('input[name="ModelArray[]"]:checked').length == 0 )
    {
        alert("You must check atleast one checkbox");
        return false;
    }
    else
        return true;
}
</script>

Let me know if this doesn't work for you.

score 1 · Answer 3 · answered May 03 '12 at 15:30

1

I would do it the following (quite clean - pure browser js) way (and tried this on jsfiddle with success)

function validateForm() {
    var i, chks = document.getElementsByName('ModelArray[]');
    for (i = 0; i < chks.length; i++)
        if (chks[i].checked)
            return true;
    alert('No value selected');
    return false;
}

answered May 03 '12 at 15:30

jJ'

3,038
32
25

this works in jsfiddle, however it does not work for me , thanks for the help though. I tried something very similar tothis myself and it didnt work – user1338194 May 03 '12 at 15:44

score 0 · Answer 4 · answered May 03 '12 at 15:23

0

Give them a unique class, e.g. 'chbValidate', then try if($('.chbValidate:checked').length == 0)

answered May 03 '12 at 15:23

JNF

3,696
3
31
64

score 0 · Accepted Answer · answered Jul 31 '12 at 07:47

0

var wrap=doc.get("checkb");
ArrCB=wrap.getelementbyTagName('input');
ArrCB_l=ArrCB.lenght();
while(ArrCB_l--){
  var CB=ArrCB[ArrCB_l];
  CB.checked()==True;
  return 1
 }
 return 0

 }

answered Jul 31 '12 at 07:47

user1338194

267
1
4
17

shadyyx · Answer 6 · 2012-05-03T15:20:50.707

-1

Try this:

if($('input[name="ModelArray[]"]:checked').length == 0) {
    alert('No checkbox is checked');
}

within Your validate function on submit.

edited May 03 '12 at 15:20

answered May 03 '12 at 15:08

shadyyx

15,825
6
60
95

Validating checkboxes using javascript in php

6 Answers6