How to check if url contains a sub-string using jQuery or javascript?

You can check if a string contains substring in javascript by taking the URL using windows.location.href and then check the sub-string using .IndexOf("Substring") method , so your complete code will be as below

if (window.location.href.indexOf("/CRM") > -1) {
   alert("Inside /CRM");
}

Or Second Method you can do it like below

if (location.href.match(/CRM/)) {
alert("in CRM ");
}

You can also try to use Regular expression in Javascript, then you can try below code to check if url contains a word or sub-string

if (/StringtoCheck/.test(window.location.href))
{
   //yes it contains
}

regex may be helpful when the condition to check a given string in URL get's little bit tricky

OR

Simply use below code

if(window.location.href.indexOf("YourStringToCheck") != -1){
   //string found code here
}