Inspect an element shown on hover

To inspect an element with Chrome DevTools, we usually right-click the element and choose Inspect from the context menu. However, it doesn't work with a dynamic element that is displayed when we hover on a given element. A JavaScript tooltip is a common example.

There are a few ways to inspect that kind of elements.

Trigger the mouseover event

Right-click the original element, and choose the Inspect menu item
Click the Console tab
Fire the `mouseover` event by excuting the following code in the Console:

$0.dispatchEvent(
    new MouseEvent('mouseover', {
        view: window,
        bubbles: true,
        cancelable: true,
    })
);

`$0` represents the current inspected element

It simulates the `mouseover` event that is supposed to happen when we hover on the original element.

Pause the script execution

Open the Chrome Developer Tools, and click the Sources tab
Hover on the target element, and click the F8 key
Move the mouse over the target element
Activate the Elements tab, and you will see the dynamic element shown up here

Use debugger

It's similar to the previous way.

In the Console, execute the following code:

handler = (e) => {
    if (e.key === 'Enter') debugger;
};
document.addEventListener('keydown', handler);

Running `debugger` here will pause the script execution when we press the Enter key. Of course, you can replace it with other key.

Hover on the target element, and click the Enter key
The dynamic element is displayed and visible under the Elements tab

Once you don't want to monitor the dynamic element anymore, you can stop listening to the `keydown` event:

document.removeEventListener('keydown', handler);

Track subtree modifications

Open the Chrome Developer Tools, and click the Elements tab
Right-click the `body` element, and choose Break on > subtree modifications from the context menu

If the dynamic element, a tooltip for example, is generated in the parent element of the target element, then you should choose the parent instead of the `body` element

Move the mouse over the target element
You will see the dynamic element shown in the Elements tab

Indicate img elements that miss alt attribute

Keep the calculation of a magic number