Javascript string replace with regex to strip off illegal characters

Question

Need a function to strip off a set of illegal character in javascript    amp       lt  gt       This is a classic problem to be solved with regexes  which means now I have 2 problems   This is what I ve got so far   var cleanString   dirtyString replace     amp        lt  gt         g         I am escaping the regex special chars with a backslash but I am having a hard time trying to understand what s going on    If I try with single literals in isolation most of them seem to work  but once I put them together in the same regex depending on the order the replace is broken   i e  this won t work --  dirtyString replace     lt  gt  g        Help appreciated

User · Answer

I tend to look at it from the inverse perspective which may be what you intended:

What characters do I want to allow?

This is because there could be lots of characters that make in into a string somehow that blow stuff up that you wouldn't expect.

For example this one only allows for letters and numbers removing groups of invalid characters replacing them with a hypen:

"This¢£«±Ÿ÷could&*()\/<>be!@#$%^bad".replace(/([^a-z0-9]+)/gi, '-');
//Result: "This-could-be-bad"

User · Answer

You need to wrap them all in a character class  The current version means replace this sequence of characters with an empty string  When wrapped in square brackets it means replace any of these characters with an empty string   var cleanString   dirtyString replace      amp        lt  gt          g

User · Answer

Put them in brackets      var cleanString   dirtyString replace      amp        lt  gt          g

User · Answer

What you need are character classes  In that  you ve only to worry about the      and - characters  and   if you re placing it straight after the beginning of the character class         Syntax   characters  where characters is a list with characters   Example   var cleanString   dirtyString replace     amp       lt  gt       g

[javascript] Javascript string replace with regex to strip off illegal characters

Examples related to javascript

Examples related to regex

Examples related to string