JS实现checkbox全选/全不选，单个复选框取消不全选

HTML：

全选


	
	
 
	
	

	
	

	
	

JS:

window.onload = function (){
	var all = document.getElementById ("all");			//全选checkbox
	var box = document.getElementsByClassName('box');	//子复选框
	
	//遍历checkbox，把子复选框的checked设置成全选框的状态，实现全选/全不选
	all.onclick = function (){
		for ( var i = 0; i < box.length; i++){
			box[i].checked = this.checked;
		}
	};
	//遍历checkbox，子复选框有一个未选中时，如果全选框设为false不选状态
	for ( var i = 0; i < box.length; i++){
		box[i].onclick = function (){
			if ( !this.checked ){
				all.checked = false;
			}
		};
	}
}