Understanding the Difference Between src Property and Attribute in JavaScript

Discover why comparing `src` values in JavaScript can lead to unexpected results and learn how to correctly handle image paths using the DOM.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Setting src through DOM vs Comparing src values

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding the Difference Between src Property and Attribute in JavaScript

If you're working on a JavaScript project that involves images, you might have encountered a peculiar issue when trying to compare the src attribute of an <img> tag. This guide will explain what causes these issues and how to resolve them effectively.

The Problem

Imagine you've created an image element in your HTML as follows:

[[See Video to Reveal this Text or Code Snippet]]

You then set and change the src of the image randomly within a setInterval function:

[[See Video to Reveal this Text or Code Snippet]]

This code works flawlessly, and the image source is updated correctly. However, when you attempt to compare the src value with the expected image path, the result is always false:

[[See Video to Reveal this Text or Code Snippet]]

What might be causing this issue? The answer lies in how JavaScript handles the src property of HTML elements.

Understanding the src Property

For example, if you log the src property:

[[See Video to Reveal this Text or Code Snippet]]

This output shows the full path to the image file on your local machine, rather than the relative path you were expecting.

The Solution

Use getAttribute() Method

To correctly compare the src of the image with your expected values, you should use the getAttribute() method. This method retrieves the value of the attribute as specified in the HTML.

Here's how you can modify your comparison:

[[See Video to Reveal this Text or Code Snippet]]

This will successfully return true when the src matches the expected relative path because you're directly accessing the attribute, rather than the absolute URL.

Summary of Key Points

The src property returns the absolute URL of the image.

To compare the src attribute with a relative path, use getAttribute('src').

Always remember that properties often return processed data, while attributes provide the original values set in HTML.

Conclusion

Understanding the distinction between the src property and the src attribute is crucial when working with images in JavaScript. By using the getAttribute() method, you can avoid unexpected results and make your comparisons work as intended. Now you can apply this knowledge to your projects with confidence! Keep coding and exploring!