Jquery Syntax error, unrecognized expression:

Question

Why do I get this error and how can I test for it so it wont break, I tried checking for null but obviously that wont work, thanks.

Please don\'t advice to not write

Answer 1

W3C has defined a new function for this this: CSS.escape(). In your example code, it would look like this:

var jsonTest = [
  {
    "myId": "''''''\"\"\"\"'''''''''''''\"#####$'''''",
  }
];

$('#' + CSS.escape(jsonTest[0].myId)).length; // Works 

Browsers don't yet support it, but there is a polyfill library that you can use in the mean time: https://github.com/mathiasbynens/CSS.escape

I've used it with success in my project.