How to correctly use the ID attribute

Implementation example: how to use the id to get inputs tab order implementation working


The HTML id attribute is a powerful feature that allow us to identify unequivocally an element in a page.
Caution: you cannot have more than one element with the same id in an HTML document.

Use cases

  • Apply styles via CSS
  • Apply HTML attributes
  • Select an element via javascript to do FILL IN YOUR NEED HERE with it
  • Etc.

How to use it correctly

It's simple if you only have 1 element to which you want to apply an id.
But, as you can't have the same id for different elements, what happens if you, for example, want to assign an id to a reusable element that can appear several times in the same page?
You can create a variable in the reusable, that variable is going to be unique for each reusable instance, even in the same page. Using 'Calculate RandomString' you can have that unique value.
Let see the application in a real example:


The case

In this case, we had a form in a popup with inputs and tooltips. The tooltips are a reusable element that appears a couple of times in the popup.
When the user try to move from one input to another using the keyboard, with the 'Tab' key, the tooltips, clickable elements, gained focus and the user had to press the 'Tab' key twice to go from an input to another when there was a tooltip in between.
The solution was to add an id to the tooltip and, using javascript, set the attribute tabIndex to -1, causing the element to be skipped when tabbing.

The problem

As the reusable appeared several times in the popup, the id wasn't unique and the javascript couldn't 'get' the element and set the attribute

The solution

  1. 1.
    In the reusable, create a variable = random string (will be unique for each instance of the reusable)
Random variable
2. In the reusable, add the id, in this case we are going to use 'noTab' + our random variable (it could have been just the random string, but using it this way is more readable for other developers and it'll help in future app maintenance)
Adding the id
3. When the element with the id is visible, we apply the 'Run javascript' action. Being visible is important because if the element is not yet rendered in the page, the javascript code is not going to be able to get the element. Then we apply the attribute tabIndex = -1.
Adding the attribute tabIndex via javascript
As you can see in the screenshot, we get the element using its id, that would be unique. This was our code:
document.getElementById('noTabvar - tooltipId's text').setAttribute('tabindex', '-1');
4. Our popup working flawlessly:
Implementation working