JS實現發送驗證碼倒計時

//點擊發送按鈕觸發事件
function sendMsg(){
	var time = 60; //設定倒計時時間爲60s
	var obj = $('#btn');//發送驗證碼按鈕對象
	settime(obj,time);
}

function settime(obj,time){
	if(time==0){
		obj.attr('disabled',false);
		obj.val("點擊發送驗證碼");
		time = 60;
		return;
	}else{
		obj.attr('disabled',true);
		obj.val(time+"s後重發");
		time--;
	}
	setTimeout(function(){
		settime(obj,time)
	},1000)
}