Even a task as simple as this can be complicated without jQuery at our disposal. In plain JavaScript, we could add the highlighted class as shown in the following code snippet:
window.onload = function() {
var divs = document.getElementsByTagName('div');
for (var i = 0; i < divs.length; i++) {
if (hasClass(divs[i], 'poem-stanza')&& !hasClass(divs[i], 'highlight')) {divs[i].className += ' highlight';
}
}
function hasClass( elem, cls ) {
var reClass = new RegExp(' ' + cls + ' ');
return reClass.test(' ' + elem.className + ' ');
}
};Listing 1.3
Despite its length, this solution does not handle many of the situations that jQuery takes care of for us in Listing 1.2, such as the following:
Properly respecting other
window.onloadevent handlersActing as soon as the DOM is ready
Optimizing element retrieval and other tasks with modern DOM methods
We can see that our jQuery-driven code is easier to write, simpler to read, and faster to execute than its plain JavaScript equivalent.