Question

I want to extend the following regex to negative numbers.

this.value = this.value.replace(/[^0-9\.]/g, "");

I tried adding minus sign doing something like this, (/[^-0-9.]/g, “”) but this allows minus sign to be entered anywhere in the number. I want to allow only one occurance of the minus sign at the beginning of the number. Later occurances of minus should be ignored.

Please help.

Answer 1

Uh, replacing every non-number character makes that a bit harder – it’s like “negating” the regex. What I came up with is a negative lookahead, preventing a minus – which would be matched by [^0-9.] – from beeing matched if it is in the beginning of the string (using a start anchor):

….replace(/(?!^-)[^0-9.]/g, "")