Question

I need to toggle two images by clicking on the parent a tag.

here is my JavaScript

$("#VerColMenu > li > a").click(function() {
    var src = ($(this).children()[0].attr('src') === 'img/plus.png')
    ? 'img/minus.png'
    : 'img/plus.png';
   $(this).children()[0].attr('src', src);
});

but nothing happens here.

Answer 1

Attaching [0] to a jQuery object retrieves the under-lying DOM object. Along with the above/below answers, you can also use .first() to get the first element in a jQuery array set:

$("#VerColMenu > li > a").click(function() {
    var src = ($(this).children().first().attr('src') === 'img/plus.png') ? 'img/minus.png' : 'img/plus.png';
    $(this).children().first().attr('src', src);
});

DEMO

This of course does have to be wrapped in $(document).ready() or something similar.