How Can I Find and Manipulate HTML Elements by Class Name in JavaScript?

Finding Elements by Class in JavaScript

While the getElementById() function is useful for accessing elements by their unique identifiers, there are situations where you need to locate elements using their classes. JavaScript does not provide a native function for this purpose, prompting the need for alternative approaches.

One solution is to leverage the getElementsByTagName() method, which retrieves all elements of a specified tag type. By iterating through these elements and inspecting their className property, you can identify those that match your target class.

The following code demonstrates how to replace the content within HTML elements based on their class:

function replaceContentInContainer(matchClass, content) {
    var elems = document.getElementsByTagName('*'), i;
    for (i in elems) {
        if ((' ' + elems[i].className + ' ').indexOf(' ' + matchClass + ' ') > -1) {
            elems[i].innerHTML = content;
        }
    }
}

In this function, we iterate through all elements on the page and check if their className property contains the specified matchClass. If a match is found, the element's inner HTML is updated with the provided content.

This approach provides a way to manipulate elements based on their classes, even though JavaScript does not offer a dedicated function for this purpose.

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