July 2, 2010
select all checkbox by one checkbox not working
Question by User123
following is my code, can any one tell me whats going wrong.
<input type="checkbox" name="Chk[]" value="<?php echo($arr['id']); ?>" onClick="Click()" id="CK">// all checkboxex
<input onClick="selectall()" type="checkbox" value="yes" name="c1">// one checkbox
/*function called*/
function selectall()
{
if(document.frm.chk.value=="false")
{
document.frm.chk.value="true";
for(var i=0; i<document.frm.elements.length; i++)
{
if((document.frm.elements[i].type)=="checkbox")
{
document.frm.elements[i].checked = true;
}
}
}
else if(document.frm.chk.value=="true")
{
document.frm.chk.value="false";
for(var i=0; i<document.frm.elements.length; i++)
{
if((document.frm.elements[i].type)=="checkbox")
{
document.frm.elements[i].checked = false;
}
}
}
}
Answer by Andy Robinson
I grabbed your code and tweaked it slightly bit rough and ready but seems to work…
<form name='frm'>
<input type="checkbox" name="chk" value="<?php echo($arr['id']); ?>" onClick="Click()" id="CK">// all checkboxex
<input onClick="selectall()" type="checkbox" value="yes" name="c1">// one checkbox
</form>
/*function called*/
<script>
function selectall()
{
if(!document.frm.chk.checked)
{
document.frm.chk.value="true";
for(var i=0; i<document.frm.elements.length; i++)
{
if((document.frm.elements[i].type)=="checkbox")
{
document.frm.elements[i].checked = true;
}
}
}
else if(document.frm.chk.checked)
{
document.frm.chk.value="false";
for(var i=0; i<document.frm.elements.length; i++)
{
if((document.frm.elements[i].type)=="checkbox")
{
document.frm.elements[i].checked = false;
}
}
}
}
</script>
Now when clicking the second checkbox it will check/uncheck the other one. Had to check the checked property rather than value.
Oh and like @Gordon said much easier to use a debugger like Firebug to find out why it’s not working. Assuming your form is called is called frm?
Answer by Starx
use document.form not document.frm
