# Need a RegExp

**URL:** <https://forum.kirupa.com/t/need-a-regexp/299959>\
**Category:** flash\
**Created:** [November 13, 2009, 12:08pm UTC](https://forum.kirupa.com/t/need-a-regexp/299959 "2009-11-13T12:08:03Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Esseti](https://avatars.discourse-cdn.com/v4/letter/e/bb73d2/32.png) [@Esseti](https://forum.kirupa.com/u/Esseti)\
**Post date:** [November 13, 2009, 12:08pm UTC](https://forum.kirupa.com/t/need-a-regexp/299959/1 "2009-11-13T12:08:03Z")

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I need some help in defining a RegExp for checking an URL. I know that there are some URL RegExp’s out there, but I need a custom one. Here’s what I have so far:  
var urlExpression:RegExp = /([a-z,A-Z][0-9]\*)(.)([a-z,A-Z]{2,4})/;  
It works ok, but I need to check before the ’ (.) ’ part if there’s a ‘space’ (or any other non alphanumeric) character before it. If there is, the result should be false.