Does string contain Ajax?

Question

I am writing a tutorial page for JavaScript and to prevent xss I want to check if the user's input contains any ajax and if it does return an error string. Also any other elements that could be used for xss in the input should make it error. What would the code for this be?

Answer 1

Try defining a RegExp including methods, strings which should not pass validation , utilize RegExp.prototype.test() with string as argument

 var re = /XMLHttpRequest|.\\.ajax|.\\.get|.\\.post|.\\.getScript|script/; var str = "$.post"; var res = re.test(str) ? new Error("error") : str; console.log(res)