<html>
<head>
<script language=javascript>
function a(c){
if(c.checked){
if(c.value==1){
document.all.a.disabled=false;
}
else{
document.all.a.disabled=true;
}
}else{
document.all.a.disabled=!document.all.a.disabled;
}
}
</script>
</head>
<body >
<input type="button" name="a" value="delete" >
<input type="checkbox" name="element1" value="1" onclick="a(this);" > abc
<input type="checkbox" name="element1" value="2" onclick="a(this);" >def</body>
</html>
<head>
<script language=javascript>
function a(c){
if(c.checked){
if(c.value==1){
document.all.a.disabled=false;
}
else{
document.all.a.disabled=true;
}
}else{
document.all.a.disabled=!document.all.a.disabled;
}
}
</script>
</head>
<body >
<input type="button" name="a" value="delete" >
<input type="checkbox" name="element1" value="1" onclick="a(this);" > abc
<input type="checkbox" name="element1" value="2" onclick="a(this);" >def</body>
</html>
<head>
<script language=javascript>
function a(c){
var o=document.all.element1;
if(o!=null && o.length>0){
if(o[0].checked){
document.all.a.disabled=true;
}
if(o[1].checked){
document.all.a.disabled=false;
}
}
}
</script>
</head>
<body onload="a();" >
<input type="button" name="a" value="delete" >
<input type="checkbox" name="element1" value="1" > abc
<input type="checkbox" name="element1" value="2" checked >def</body>
</html>