Question

I am just starting out with javascript so please pardon me if my question seems stupid. I want to design a webpage with some checkboxes such that when the first one is checked, the others become enabled. How do I do that using JS? I wrote the following code:

function checkBox() {
    if (window.document.form1.mainbox.checked=true) {
        for (i=0;i<window.document.form1.Others.length;i++) {
            window.document.form1.Others[i].disabled=false;
        }
    }
    else {
        for (i=0;i<window.document.form1.Others.length;i++) {
            window.document.form1.Others[i].disabled=true;
        }
    }
}

And this html:

<form name="form1">
<input name="mainbox" value="mainbox" onclick="checkBox()" type="checkbox"> Mainbox<br>
<input disabled="disabled" checked="checked" tabindex="0" name="Others"   type="checkbox">No. 1<br>
<input disabled="disabled" checked="checked" tabindex="1" name="Others" type="checkbox"> No. 2<br>
<input disabled="disabled" checked="checked" tabindex="2" name="Others" type="checkbox"> No. 3<br>
</form>

The problem is that on the first click the other checkboxes do become enabled, but nothing happens on the subsequent clicks, i.e. they do not become disabled again. How do I correct this problem? Any help will be appreciated. Thanks!

EDIT

I followed the suggestion of gabitzish and it worked. However, I now want to pass Others as a parameter, so I write:

<input name="mainbox" value="mainbox" onclick="checkBox(Others)" type="checkbox"> Mainbox<br>

and modify the script as follows:

window.checkBox = function(chkname) {
    if (window.document.form1.mainbox.checked==true) {
        for (i=0;i<window.document.form1.chkname.length;i++) {
            window.document.form1.chkname[i].disabled=false;
        }
    }
    else {
        for (i=0;i<window.document.form1.chkname.length;i++) {
            window.document.form1.chkname[i].disabled=true;
        }
    }
}

But this does not work. Please help me out here. I will be very thankful.

Answer 1

I’ve created a jsFiddle with your code, and some minor changes : http://jsfiddle.net/CUeDg/1/

The problem with the original code was that checkBox() function was not found on click.

Edit:
Here is a solution to later edit of your question: http://jsfiddle.net/CUeDg/3/
I’ve passed the param to the function as a string.

Later edit:
I suspect that you need that param to know what set of checkboxes you need to toggle. I made a jsFiddle for that too: http://jsfiddle.net/CUeDg/5/
(If I suspected wrong, don’t consider this part of the answer)