JSFiddle - React, Tailwind, and code Playground

JavaScript

/*
 Grabbing only digits in this example
 /i - ignore case
*/
var pattern1 = /.*EmployeeId=(\d+)/i; 
var url1 = 'http://www.test.com?Name=ABC&EmployeeId=123';
var url2 = 'http://www.test.com?Name=ABC&employeeid=123';

alert(url1.match(pattern1)[1]);  
alert(url2.match(pattern1)[1]);