Select and deselect all checkboxes

[chrismassey]

I have javascript which I have incorporated into a PHP script which allows me to select all the checkboxes within a group by checking the 'check all' checkbox. The script is as follows...

Javascript:

<!--

function check_all(field, value) {
for (var i=0;i<document.forms[1].elements[field].length;i++) {
if(value == 1) {
document.forms[1].elements[field][i].checked = true
} else {
document.forms[1].elements[field][i].checked = false
}
}
}

// End -->

HTML Form:

<input type="checkbox" name="checkall" value="" onClick="check_all('checkbox[]',1)">

<input type="checkbox" name="checkbox[]" value="$file">
<input type="checkbox" name="checkbox[]" value="$file">
<input type="checkbox" name="checkbox[]" value="$file">

To deselect all checkboxes I must set the value to e.g. 2 so...

onClick="check_all('checkbox[]',2)"

However this means that I must have 2 checkboxes, 1 for selecting all and another for unselecting all. I would like this to be done within 1 checkbox.

I also have another script which does exactly what I want, however due to PHP my checkbox names must be followed by [] (array) to be able to pick up the data, and the javascript fails if I do this in the javascript below...

<!-- Begin
function Check(chk)
{
if(document.form.checkall.checked==true){
for (i = 0; i < chk.length; i++)
chk[i].checked = true ;
}else{

for (i = 0; i < chk.length; i++)
chk[i].checked = false ;
}
}

// End -->

<input type="checkbox" name="checkall" value="" onClick="Check(document.form.check)">

Therefore i tried to incorporate this line in the former script...

if(document.form.checkall.checked==true){

however it hasn't worked. Can someone please help me in trying to adapt the 1st script to suit my needs. Thanks alot,

Chris

 

[Clueful]

It's this simple:

<script type="text/javascript">

function check_all(group, action)
{
 for (var i=0; i<group.length; i++)
  group[i].checked = action;
}

</script>

<form>
<input type="checkbox" name="checkall" value="" onClick="check_all( this.form['checkbox[]'], this.checked )">

<input type="checkbox" name="checkbox[]" value="$file">
<input type="checkbox" name="checkbox[]" value="$file">
<input type="checkbox" name="checkbox[]" value="$file">
</form>