Regular expression for a real number with comma or dot for JavaScript

Question

I want to know what I'm doing wrong in this code for checking a real number:

var regex = new RegExp(/([0-9]+[\.|,][0-9]*)|([0-9]*[\.|,][0-9]+)|([0-9]+)/g);
var invalid = this.value.match(regex);

The above doesn't work for me while the expression

([0-9]+[\.|,][0-9]*)|([0-9]*[\.|,][0-9]+)|([0-9]+) 

works in the tester.

Answer 1

Do

var regex = new RegExp("([0-9]+[.|,][0-9])|([0-9][.|,][0-9]+)|([0-9]+)/g);([0-9]+[.|,][0-9])|([0-9][.|,][0-9]+)|([0-9]+)", 'g');

or

var regex = /([0-9]+[.|,][0-9])|([0-9][.|,][0-9]+)|([0-9]+)/g​;

Two constructs are possible : new RegExp(string,'g') or /somestring/g. Don't mix them. In your case of a constant regexp, it will be more efficient to choose the second one because it is precompiled.

See the MDN documentation