<div id="div1">
<input type="checkbox" onclick="selectCheckBoxes('div1', this.checked)" />全選<br/>
<input type="checkbox" /><br/>
<input type="checkbox" /><br/>
<input type="checkbox" /><br/>
</div>
<br/>
<div id="div2">
<input type="checkbox" onclick="selectCheckBoxes('div2', this.checked)" />全選<br/>
<input type="checkbox" /><br/>
<input type="checkbox" /><br/>
<input type="checkbox" /><br/>
</div>

<script type="text/javascript">
function selectCheckBoxes(domId,value) {
var inputs = document.getElementById(domId).getElementsByTagName("input");
for(var i = 0; i < inputs.length; i++) {
if (inputs[i].type == 'checkbox') {
inputs[i].checked=value;
}
}
}
</script>