JAVASCRIPT

regex do not contain

^((?!word).)*$

// Test
/^((?!word).)*$/gi.test('Should not contain word') // Returns false
/^((?!word).)*$/gi.test('John Doe') // Returns true

regular expression should not contain special character

//Author: Mohammad Arman Khan
//Regular Expression should not contain Special Characters
var regex = /^[A-Za-z0-9 ]+$/;

Regex not contains

^((?!hede).)*$

regex not contains

^(?!keyword).*
 // Regex pattern to find lines that do not contain keyword, incl newline