如何将Id设置为使用Javascript创建的按钮？

Question

//如何设置此创建按钮的ID？

for(i=1;i<=3;i++)
{       
    var btn = document.createElement("BUTTON");// create       button using java script
    btn.className = "btnsize";

    var txt = document.createTextNode(num++);//creat text on button
    btn.appendChild(txt);//attached text on button
    document.getElementById("xyz").appendChild(btn);//atache button with text in div 
} 

Answer 1

btn.id = "btnid"+i

这将相应地编号

Answer 2

for (i = 1; i <= 3; i++) {
 var btn = document.createElement("BUTTON");
 btn.setAttribute("class","btnsize");
 btn.setAttribute("id","btnid"+i);
 var txt = document.createTextNode("button");
 btn.appendChild(txt);
 document.getElementById("xyz").appendChild(btn); 
}

Answer 3

html

<div id="xyz"></div>

js

for (i = 1; i <= 3; i++) {
    var btn = document.createElement("BUTTON");// create       button using java script
    btn.className = "btnsize";
    btn.id = "btnid"+ i;
    var txt = document.createTextNode("aaasasa");//creat text on button
    btn.appendChild(txt);//attached text on button
    document.getElementById("xyz").appendChild(btn);//atache button with text in div 
}  

DEMO

您的代码num未定义。您应该在i中为唯一ID添加btn.id = "btnid"+ i;。