Question

I’ve tried several methods found on this site to get my script to change “+” and “-” expand/collapse button images, but I haven’t yet found a suitable fix/method.

Currently, I am using plain JS as follows:

function swapimg(id) {
if(document.getElementById(id).src='images/bullet_expand.png')
{document.getElementById(id).src='images/bullet_expanded.png'}
else {document.getElementById(id).src='images/bullet_expand.png'}
}

and the button:

<a href="javascript:void();" onclick="toggle_visibility('item1'); swapimg('phb');">
<img src="images/bullet_expand.png" border="0" style="padding-right: 5px;" id="phb" alt="">
</a>

The first click does change the image, but the second click does nothing. I have a feeling using “getElementById” might not be the standard call, so using JQuery is also an option I will consider.

Answer 1

Instead of comparing you are assigning the value, you need == and not =

Instead of this:

document.getElementById(id).src='images/bullet_expand.png'

use

document.getElementById(id).src=='images/bullet_expand.png'

jQuery:

if(jQuery('#'+id).attr('src') == 'images/bullet_expand.png') {
   jQuery('#'+id).attr('src','images/bullet_expanded.png');
} else {
   jQuery('#'+id).attr('src','images/bullet_expand.png');
}

Javascript:

if(document.getElementById(id).src.indexOf('/images/bullet_expand.png') > 0) {
    document.getElementById(id).src='images/bullet_expanded.png';
}
else {
    document.getElementById(id).src='images/bullet_expand.png';
}