关于 event 对象 event 在函数内部可以直接读取

event

function ch(e){
			console.log(e)
			var e  = e||event;
			var text  = e.target.value;
			a.b = text;
			console.log(a.b)
		}

	function ch(){
			var e  = e||event;
			console.log(e)
			var text  = e.target.value;
			a.b = text;
			console.log(a.b)
		}

function ch(){
			console.log("event",event)
			var text  = event.target.value;
			a.b = text;
			console.log(a.b)
		}