jQuery - how to check if two elements are the same?

Comparing JQuery objects will never return true, because each JQuery object is a a new object, even if their selectors are equal.

To compare elements, you have to check whether the DOM elements are equal:

this === element.get(0);

Use isEqualNode to check if two elements have the same markup

this.isEqualNode(element)

Or use isSameNode to check if two elements are the same DOM node

this.isSameNode(element)

You don't have to. You're always applying the special style to one specific element, so color them all, and then change the color of the specific element.

function colorize(element) {
    element.parent().find('span').each(function() {
        $(this).css('background','pink');
    });

    element.css('background','yellow');
}

The problem with your comparison was that you were comparing two objects (jQuery objects). When comparing objects, unless they're pointing to the same thing, they are considered unequal:

var o1 = {};
var o2 = {};
o1 !== o2;

You can work around this by removing the jQuery wrapper:

function colorize(element) {
    var realElement = element[0];

    element.parent().find('span').each(function() {
        if (this === realElement) {
            $(this).css('background','yellow');
        } else {
            $(this).css('background','pink');
        }
    });
}

This way, you're comparing DOM elements to DOM elements, and not apples to oranges or objects to objects.

You can use the jQuery is() function. The original answer can be found here.

function colorize(element) {
    element.parent().find('span').each(function() {
        if ( $(this).is(element) ) {
            $(this).css('background','yellow');
        } else {
            $(this).css('background','pink');
        }
    });
}