Regular Expression Validation problem

[zerosix]

I have a field named 'Dimension -1-' that requires validation. The input should be considered invalid if it matches the pattern of a positive floating-point number, followed by the lowercase letter 'x', and then another positive floating-point number, where both floating-point numbers use a comma as the decimal separator (example 123,2x12,1). I attempted to use the regular expression \b\d+,\d+x\d+,\d+\b to validate this format, but it's not functioning . Could you assist me in identifying the issue( the regular expression is correct) ?

[yuri]

A regular expression should start and end with a slash character. Maybe this is a cause of the problem.

[zerosix]

yes, that's it, thank you so much