var Odiv=document.createElement("div");
Odiv.style.cssText="width:200px;height:200px;background:#636363;text-align:center;"; 
var dinput=document.createElement("input");
dinput.type = "button"
dinput.value = "返回";
dinput.id = "return1"
Odiv.appendChild(dinput);      
var dinput1=document.createElement("input");
dinput1.type = "button"
dinput1.value = "確定";
Odiv.appendChild(dinput1);        //在div內建立一個span
    document.body.appendChild(Odiv);        //在body內建立一個div 
    var aa = document.getElementById("return1")
    aa.onclick=function(){
    console.log("this");
    }
    console.log(aa.getAttribute("id"));