为什么我得到“ReferenceError：getElementById未定义”？

Question

I have a little JavaScript code I wrote, and for some reason I'm getting an error saying:

ReferenceError: getElementById is not defined

Here is the function:

window.onload=function() 
{ 
    clearAll(); 
    updatePizzaToppings(); 
    updatePizzaToppings(); 
    updatePizzaToppings(); 
    updatePizzaToppings(); 
};


function updatePizzaToppings() 
{ 
    var checkBox=getElementById('selectBacon'); 
    var pic=getElementById('BaconPic'); 
    if (checkBox.checked) 
    {
        pic.style.visibility='visible'; 
    }
    else 
    {
        pic.style.visibility='hidden';
    }           
}; 

I've made a little JSFiddle for it as well.

http://jsfiddle.net/CkjkB/5/

Answer 1

你需要使用document.getElementById()