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benton · 12-27-2008, 06:42 PM

I have a form that dynamically creates checkboxes. I want to put a checkbox above those so that the user can click on it to check/uncheck all of them at once. But I can't figure out how to find the checkboxes. Here's what I am trying to do:

This creates the single checkbox that I want to click to toggle all the others.

PHP Code:


			
<input type="checkbox" name="checkall" onclick="ChangeCheckStatus();">

Later in the form is the code to create the individual checkboxes.

PHP Code:


			
for ($i = 0; $i < $some_variable; ++$i)

{

  <input type="checkbox" name="checkall_"<?php echo $i; ?>">

}

I know I will need to do a loop to see them all but I used the following just to see if the basic code is working. But when I click on the main checkbox, nothing is displayed. If I change the alert to alert(elm.length);, it displays the total number of input form elements, as expected. Would someone please point out my mistake or let me know if there is a better way to do this?

HTML Code:

<script type="text/javascript">
function ChangeClickedStatus()
{
 var elm = document.getElementsByTagName("input");
 alert(elm[0].name);
}
</script>

12-27-2008, 06:42 PM	#1 (permalink)
benton The Contributor Join Date: Apr 2008 Posts: 78 Thanks: 0	How to locate certain checkboxes I have a form that dynamically creates checkboxes. I want to put a checkbox above those so that the user can click on it to check/uncheck all of them at once. But I can't figure out how to find the checkboxes. Here's what I am trying to do: This creates the single checkbox that I want to click to toggle all the others. PHP Code: `<input type="checkbox" name="checkall" onclick="ChangeCheckStatus();">` Later in the form is the code to create the individual checkboxes. PHP Code: `for ($i = 0; $i < $some_variable; ++$i) { <input type="checkbox" name="checkall_"<?php echo $i; ?>"> }` I know I will need to do a loop to see them all but I used the following just to see if the basic code is working. But when I click on the main checkbox, nothing is displayed. If I change the alert to alert(elm.length);, it displays the total number of input form elements, as expected. Would someone please point out my mistake or let me know if there is a better way to do this? HTML Code: <script type="text/javascript"> function ChangeClickedStatus() { var elm = document.getElementsByTagName("input"); alert(elm[0].name); } </script>