Difference Between ID and Class

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ID's area unit distinctive

Each component will have only 1 ID
Each page will have only 1 component therewith ID
When I was 1st learning these things, I detected over and over that you simply ought to solely use ID's once, however you'll use categories over and over. It essentially went in one ear and out the opposite as a result of it plumbed a lot of sort of a sensible "rule of thumb" to ME instead of one thing extraordinarily necessary. If you're strictly AN HTML/CSS person, this perspective will persist as a result of to you, they extremely do not appear to try to to something completely different.

Here is one: your code won't pass validation if you employ constant ID on quite one component. Validation ought to be necessary to all or any folks, in order that alone may be a huge one. We'll re-evaluate a lot of reasons for individualism as we have a tendency to continue.

Classes don't seem to be distinctive

You can use constant category on multiple components.
You can use multiple categories on constant component.
Any styling info that must be applied to multiple objects on a page ought to be through with a category. see example a page with multiple "widgets":