How to enable javascript if checkbox selected

[Pandya]

I have inserted some 2 or 3 check boxes in to my web application when I wanted to set the validation on each check box, the check box should give the portability that once any one of check box has been selected the other two options should get checked automatically, Is it possible to enable with my application.

[Timothi]

Checkboxes are a great way to get directed input from people using your site. Sometimes you may want to limit the amount of checkboxes that can be selected at any one time. This may come in handy during form validation.

function CheckNewRequest() {
   var boolIsChecked = w.indefinite.checked;
   if (w.disksize.options[w.disksize.selectedIndex].value.length < 1) {
          alert("Please select the Disk Size you are requesting to use");
          w.disksize.focus();
          return false;
   }

[Arkad]

A check box has a checked property, which returns either a 0 for not checked and a 1 for checked. You can also set the property to 0 or 1 to programmatically control the check box. A simple loop checks each checkbox value for input, tallies up a count that were selected, and a couple of simple tautologies will display an appropriate message depending on the input.

[Sadashiva]

The HTML INPUT tag, with "checkbox" as the value of the TYPE attribute. For a given form, the JavaScript runtime engine creates appropriate Checkbox objects and puts these objects in the elements array of the corresponding Form object.

function checkCheckBoxes() {
	if (document.frmTest.CHKBOX_1.checked == false &&
	    document.frmTest.CHKBOX_2.checked == false &&
	    document.frmTest.CHKBOX_3.checked == false)
		{
		alert ('You didn\'t choose any of the checkboxes!');
		return false;
		}
	else
		{
		return true;
		}
	}