php - Is it always bad practice to start an ID with a number? (CSS)

Question

In my project I have submissions and comments, each with an ID. Currently the ID's are just numeric and correspond to their database ID's. Everything is working fine but when I run it through the W3 validator I get the error:

value of attribute "id" invalid: "1" cannot start a name

I suppose instead that I could just precede all ids with some sort of string but then whenever I was using or manipulating the id in JQuery or PHP I have to do a id.replace('string', '') before using it. This seems rather cumbersome. Any advice?

Answer 1

Yes, using numbers as HTML element IDs is bad practice.

1. It violates W3C specification.
   You noted this in your question, and it is true for every HTML specification except HTML5

2. It is detrimental to SEO.
   Search-engine optimized HTML element IDs SHOULD reflect the content of the identified element. Check out How To Compose HTML ID and Class Names like a Rockstar by Meitar Moscovitz. It provides a good overview of this concept.

3. There can be server-side scripting issues.
   Back when I first started programming in ASP classic, I had to access submitted form fields by a syntax like Request.Form("some_id"). However, if I did Request.Form(1) it would return the value of the second field in the form collection, instead of the element with an Id equal to 1. This is a pretty standard behavior for working with collections. Its also similar with javascript, and could make your client side scripting more complicated to maintain as well.