Do search engines care about case sensitivity?

Question

Which is better for SEO ?

HTML

1. <p id="hello"></p>

2. <p id="HELLO"></p>

3. <p id="Hello"></p>

4. <p id="hELLO"></p>

JAVASCRIPT

1. function hello(){}

2. function HELLO(){}

3. function Hello(){}

4. function hELLO(){}

Answer 1

Case sensitivity doesn't matter for SEO. HTML, when used properly, does offer search engines clues about the content of a page but whether those tags and their attributes are capitalized or not is irrelevant. (Although it may matter for validating your HTML depending on the Doctype you choose).

Most search engines don't read JavaScript so that point may be moot. But even if they did the case of function names are also irrelevant.

Answer 2

It most likely doesn't matter at all.

Answer 3

I don't think search engine bots bother about html elements, element id's or javascript in the pages, let alone if id's or function names are upper- or lower case. It's headers and content that's interesting for SEO.