Select All js

<SCRIPT type="text/javascript">
function markall(id)
{id=document.getElementById(id); var i=0; while(id.elements[i]){ if(id.elements[i].type == "checkbox") {id.elements[i].checked=1;} i++;}}
        
function unmarkall(id)
{id=document.getElementById(id); var j=0; while(id.elements[j]){ if(id.elements[j].type == "checkbox") {id.elements[j].checked=0;} j++;}}
            
function invert(id)
{id=document.getElementById(id); var k=0; while(id.elements[k]){if(id.elements[k].checked == 1) {if(id.elements[k].type == "checkbox") {id.elements[k].checked=0;}} 
else {if(id.elements[k].type == "checkbox") {id.elements[k].checked=1;}} k++;}}
            
function resetall(id)
{id=document.getElementById(id); var i=0; while(id.elements[i]){ if(id.elements[i].type == "checkbox") {id.elements[i].checked=id.elements[i].defaultChecked;} i++;}
}               
</SCRIPT>   

<form method="post" name="watchlist" id="watchlist" action="">
<input type="checkbox" name="watched[391295]" id="x391295" value="1">
</form>

Select: <a href="javascript:markall('watchlist');">All</a> :: <a href="javascript:unmarkall('watchlist');">None</a> :: <a href="javascript:invert('watchlist');">Invert</a> :: <a href="javascript:resetall('watchlist');">Reset</a>