Changing a Firefox extension's toolbar color in response to signal

Question

I am making a firefox extension, and I would like the background-color of my toolbarbutton to change in response to a message in an xmlhttp request. This is what I have, but it doesn't work:

    if(x.section == 1)
    {
        var element = document.querySelector('#custom-button-1');
        element.style.backgroundColor = green;
    }

    if(x.section == 0)
    {
        var element = document.querySelector('#custom-button-1');
        element.style.backgroundColor = red;
    }

I know that the problem isn't x.section because did some testing with alerts. Do you know what I'm doing wrong?

Answer 1

You need to change the color values to strings (with quotes):

element.style.backgroundColor = 'red';

or

element.style.backgroundColor = "red";