JS-複選框的全選與全不選

function selectAll(){
	var checklist = document.getElementsByName ("selected");
	if(document.getElementById("controlAll").checked){
		for(var i=0;i<checklist.length;i++){
			checklist[i].checked = 1;
		}
	}else{
		for(var j=0;j<checklist.length;j++){
			checklist[j].checked = 0;
		}
	}
}

<form>
	<input onclick="selectAll()" type="checkbox"   name="controlAll" id="controlAll"/>全選<br>
	1:<input type="checkbox" name="selected" value="1"/><br>
	2:<input type="checkbox" name="selected" value="2"/><br>
	3:<input type="checkbox" name="selected" value="3"/><br>
	4:<input type="checkbox" name="selected" value="4"/><br>
	5:<input type="checkbox" name="selected" value="5"/><br>
	6:<input type="checkbox" name="selected" value="6"/><br>
</form>