Question

I would like to search all over thousands of HTML code for bad practice of height, width or any other CSS.

for instance I would like to get all places where height is not provided with units, for instance height:40 should be found, but height:40px shouldn’t.

For that I am using the search program agent ransack, in which I can put regular expression to search within files.

Currently my regular expression is:

(height:)[\s]*[0-9]*\.?[0-9]+(px) 

this finds everything that is like height:40px. (Later on I want to add width, or other things)

My question is how to make a NOT on top of all that?

Or is there any other good application to search files for regular expressions?

Answer 1

Use a negative lookahead (?!regex), eg:

height:\s*\d+(?:\.\d+)?(?!px|\d)

\d is needed to prevent backtracking alternatives from matching.