Javascript，将div颜色设置为另一种divs颜色

Question

I tried:

document.getElementById('colorsdiv').style.backgroundColor =
    document.getElementById(thediv).style.backgroundColor;

I know thediv is valid, because if I do: document.getElementById(thediv).style.backgroundColor = 'red';

it turns red.

If I do: alert(document.getElementById(thediv).style.backgroundColor); it is null .

I also know that it is set to a color in my stylesheet because it displays that way.

What do I need to do to get this to work?

Answer 1

To get the current style of another element, use this:

if( typeof getComputedStyle == "undefined")
    getComputedStyle = function(elem) {return elem.currentStyle;};

document.getElementById('colorsdiv').style.backgroundColor
    = getComputedStyle(document.getElementById(thediv)).backgroundColor;

Answer 2

Did you make sure the javascript that finds the div's color is run after the page has completely loaded, eg it is in your body section of the html. This makes sure the page has loaded and rendered the color so the script can retrieve it when it is run.