<label><input type="button" name="select" onClick="selAll()" value="全选"/></label>
<label><input type="button" name="select" onClick="noSelAll()" value="反选"/></label>
<script type="text/javascript">
function selAll(){
	var a = document.getElementsByTagName("input");
	for(var i = 0;i<a.length;i++){
		if(a[i].type == "checkbox") a[i].checked = true;
	}
}
function noSelAll(){
	var a = document.getElementsByTagName("input");
	for(var i = 0;i<a.length;i++){
		if(a[i].type == "checkbox") a[i].checked = false;
	}
}
</script>