Enabling A Tag Click Event To Open A Page In A New Tab With Ctrl Or Command Key Press

Table of contents

• Introduction
• Detecting control or command key combo
• Check if the link is meant to open externally
• Detecting mouse middle button key press
• Detecting shift key press
• Putting it all together

Introduction

When you intercept a click on an A tag using the onclick event and override the default behavior using event.preventDefault();, it's now up to you to define its new behavior.

Let's say you want to load a locally cached version of the requested page. A problem arises when the user combines the link click with the Ctrl or Command key.

In such cases, to open up the page in a new tab, you don't want to serve the user with the cached page in the current tab. Instead, you might want to revert to the default behavior of opening the page in a new tab.

Detecting control or command key combo

Here is the code to detect when the A tag is clicked with either the Ctrl or command key pressed down.

Ctrl was pressed
🚫 Wrap Code📋 Copy
01: anchor.addEventListener('click', function (event) {
02:     if (event.ctrlKey || event.metaKey) {
03:         return;
04:     }
05:     event.preventDefault();
06:     // Your code here
07: });

Check if the link is meant to open externally

You might also want to check if the tag has target set to blank.

Check if target is set
🚫 Wrap Code📋 Copy
01: anchor.addEventListener('click', function (event) {
02:     if (event.ctrlKey || event.metaKey || this.getAttribute('target')) {
03:         return;
04:     }
05:     event.preventDefault();
06:     // Your code here
07: });

Ideally, you should check for this before setting the onclick event.

Detecting mouse middle button key press

Some mice open a page when clicking the middle button. This can be handled by checking if the middle button is pressed using the event.button.

The click event will only be triggered if the mouse is mapped to open a page when clicked.

Check if middle mouse button is pressed
🚫 Wrap Code📋 Copy
01: anchor.addEventListener('click', function (event) {
02:     if (event.ctrlKey || event.metaKey || this.getAttribute('target') || event.button === 1) {
03:         return;
04:     }
05:     event.preventDefault();
06:     // Your code here
07: });

Detecting shift key press

Similar to the middle mouse button, pressing down on the Shift key and then clicking on an A tag can cause the page to open.

Check if shift is pressed
🚫 Wrap Code📋 Copy
01: anchor.addEventListener('click', function (event) {
02:     if (event.ctrlKey || event.metaKey || this.getAttribute('target') || event.shiftKey || event.button === 1) {
03:         return;
04:     }
05:     event.preventDefault();
06:     // Your code here
07: });

Putting it all together

Alright, let's put everything together.

Complete code
🚫 Wrap Code📋 Copy
01: anchor.addEventListener('click', function (event) {
02:     if (event.ctrlKey || event.metaKey || this.getAttribute('target') || event.shiftKey || event.button === 1) {
03:         return;
04:     }
05:     event.preventDefault();
06:     // Your code here
07: });

It's important to note that this is more of a "whitelisting" approach, meaning a user might have some kind of key mapping that we are unaware of.

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