Javascript Count Checked Checkbox

I know that may have a few similar questions @stackoverflow, but I didnt found any solution to my problem yet :s

Solution 1:

The main problem is that you're not using the i index within the loop to reference the individual checkboxes, and you've got a . just before the [ which is a syntax error. So change:

if(document.form1.["checkbox-1[]"].checked) chkCnt++;

To:

if(document.form1["checkbox-1[]"][i].checked) chkCnt++;

But you can neaten up the function somewhat as follows:

function isCountCheck(helperMsg) {
    var i, dLen = document.form1["checkbox-1[]"].length;
    // if the length property is undefined there is only one checkbox
    if (typeof dLen === "undefined") {
        if (document.form1["checkbox-1[]"].checked) return true;
    }
    else {
        for (i = 0; i < dLen; i++) {
            if (document.form1["checkbox-1[]"][i].checked) return true;
        }
    }
    alert(helperMsg);
    return false;
}

Demo: http://jsfiddle.net/nnnnnn/ZjK3w/1/

Or just loop through all inputs in the form, checking the type (and/or the name) of each one:

function isCountCheck(helperMsg) {
    var i, len, inputs = document.form1.getElementsByTagName("input");
    for (i = 0, len = inputs.length; i < len; i++) {
        if (inputs[i].type === "checkbox"
            && inputs[i].checked)
            return true;
    }
    alert(helperMsg);
    return false;
}

Demo: http://jsfiddle.net/nnnnnn/ZjK3w/2/

Solution 2:

Simplest solution:

var form = document.forms[0]; // your form element (whatever)
var checkedElms = form.querySelectorAll(':checked').length;

No need for jQuery. Supported down to IE8. use polyfill for older browsers if you wish.

Solution 3:

Use Jquery:

function isCountCheck(helperMsg){
    if($("input[type=checkbox]:checked").length > 0)
        return true;
    alert(helperMsg);
    return false;
}

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