Visualforce - Beyond Basics Series 29 - Reference element using $Component

Is Id attribute really Unique ?

Each component in the Visualfroce page will generate an Id attribute value. If you specify one, it will be used as the suffix. So, it will be unique for the entire page.

What is the Scope of it ?

Since, the automatic Id generation is based on the parent hierarchy, it will be unique across different components embedded in the same page.

How to refer Component in Visualforce Context ?

In visualforce context, for example in reRender, Status attributes, you can specify the Id value directly.

How to refer Component in Window Context ?

But, in the browser, in Javascript or in HTML page, you should use $Component to refer them. Because, that will give you the automatically generated Id.

Where it will be useful ?

It will be useful when you want to refer them in Javascript or in HTML tags or even in CSS. you can use them pretty much anywhere in the page to refer them dynamically.

Where is the code ?

I have illustrated the example to show $Component being used in HTML, CSS & Javascript to refer the components dynamically