Limit the number of checkboxes checked

[Rio]

Hi,

I'm making an online form-to-mail form (using mail() function in PHP) with 10 checkboxes. There's nothing complicated about this page, but the viewers shoule only choose 3 checkboxes.

Is there any way to limit the number of boxes checked? It would be even better if it returns the error message when a viewer selects more than 3 boxes.

Somebady told me that the javascript is the answer

[makeda]

Yes, start out by setting a global variable equal to 0:

Then set a function to fire each time someone clicks on a checkbox. If the checkbox is checked, increment the counter, if the checkbox is unchecked, decrement the counter. If someone checks a checkbox and your counter is equal to three, uncheck the checkbox and throw an error


<script type="text/javascript">
var iCounter = 0;


function checkCounter(refChkBox) {

//if they checked the checkbox do this
if(refChkBox.checked) {

//3 checkboxes have been checked
if(iCounter >= 3) {
refChkBox.checked = false;
alert("You can only select 3 checkboxes.");
}
else {
iCounter++;
}

//if they unchecked the checkbox, do this
else {
iCounter--;
}

}

</script>

<input type="checkbox" id="chkOne" value="" onClick="checkCounter(this)" />


I haven't tested this, but it should work.

[Rio]

Thanks makeda. Guys in PHP forum helped me to do the job in php this time around. But I will try your script on non-php sites.

Chrees!

[makeda]

what??!! server side INSTEAD of client-side??!!

only kidding

good luck.