Plain JavaScript versus jQuery
Even a task as simple as this can be complicated without jQuery at our disposal. In plain JavaScript, we could add the highlight
class this way:
window.onload = function() { const divs = document.getElementsByTagName('div'); const hasClass = (elem, cls) => new RegExp(` ${cls} `).test(` ${elem.className} `); for (let div of divs) { if (hasClass(div, 'poem-stanza') && !hasClass(div, 'highlight')) { div.className += ' highlight'; } } };
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:
- Properly respecting other
window.onload
event handlers - Acting 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.