Jquery first child of "this"

javascript

prompt-engineering

performance

best-practices

byAnton Shumikhin·Feb 27, 2025

To swiftly get the first child of a jQuery object, employ either .children().first() or find(':first-child') for a clear-cut, foolproof selection.

// As concise as a one-liner joke
$(this).children().first();

// Or, using find if you like variety
$(this).find(':first-child');

Both demand minimal typing and give you the first child—perfect for speedy coding scenarios.

children() vs. find(): A Comparative Study

The .children() and .find() functions do the same: fetch the first child. However, they're as unique as twins with different preferences. .children() is the hasty one, searching only among immediate offspring. At the same time, .find() isn't afraid of a little effort, venturing way deep into the DOM tree, even though it might mean more time and computational resources.

// For those who like speed
$(this).children(":first");

// If you have time to spare, dig deeper!
$(this).find(">:first-child");

Noted developer and community guru, Jørn Schou-Rode, recommends .children() as it's not only snappy but delivers the goods in fewer letters, just like a witty tweet. It's akin to accessing element.firstChild directly, which trumps jQuery with its quicker execution.

Why Native DOM is a Speedster

While jQuery pampers you with a simplified, cross-browser syntax, it's worth noting the performance advantages of unprocessed, native DOM methods. The this.firstChild method in plain JavaScript outpaces any jQuery function in obtaining the first child, making it crucial for performance-sensitive applications.

// JavaScript's version of Flash
let firstChild = this.firstChild;

But remember, native methods might need extra compatibility checks for friendliness with older browsers.

Power Moves: Class Toggling

Frequently, one might need to flip a class on and off on the first child. It's jQuery's job to make it look like a walk in the park:

// Like a light switch, but for classes
$(this).children().first().toggleClass("fancyClass");

// Same task, different function
$(this).find(">:first-child").toggleClass("fancyClass");

These commands ensure the first child—and only the first child—is affected, no matter how many sibling elements exist.

Navigating between jQuery Objects & DOM Elements

At times, you might need to switch from a jQuery object to a native DOM element to employ the latter's properties and methods. Here, .get(0) or the array reference [0] is your guide.

// It's like having the ability to shapeshift
var domFirstChild = $(this).children().first().get(0);

This lets you wield more control and wield other DOM APIs for intricate operations.

Handle with Care: Special Cases

While dealing with dynamic content, don't forget to ensure the first child's selection remains unchanged by properly binding event handlers or using .on() for event delegation.

Note also that when using :first-child, CSS and jQuery might differ subtly in edge cases, as languages sometimes do—like when dealing with text nodes or comment nodes.

Sharpening your Selection with Advanced Techniques

Super-selective: If the first child is not your target, use .filter() to be choosier.
Existence check: Use .length to ensure the first child isn't imaginary.
Switchback methods: Use .end() to revert back after venturing among the children.
Tip for speed: Cache $(this).children() in a variable to avoid repeated deep dives into the DOM tree.