Chrome Extensions: Uncaught Error: Syntax error, unrecognized expression: a[href^=file://]

Chrome Extensions: Uncaught Error: Syntax error, unrecognized expression: a[href^=file://]

Hi there, 

I have the following code for the chrome extension:
But I got the following error.

Does anybody knows what is the problem with this expression?

Code
  1. var flag = 'Chrome_LocalLinks_extension_was_already_injected_in_this_document';
  2. if (!document[flag])
  3.   $('a[href^=file://]').
  4.     live('mousedown', handleMousedownOnLink).
  5.     live('mouseout',  handleMouseoutOnLink).
  6.     live('mouseup',   handleMouseupOnLink).
  7.     live('click',     handleClickOnLink)
  8.   document[flag] = true;
  9. }
Error In chrome debugger

Uncaught Error: Syntax error, unrecognized expression: 
a[href^=file://]
ga.error @ jquery-2.1.4.min.js:2
ga.tokenize @ jquery-2.1.4.min.js:2
ga.select @ jquery-2.1.4.min.js:2
ga @ jquery-2.1.4.min.js:2
n.fn.extend.find @ jquery-2.1.4.min.js:2n.f
n.init @ jquery-2.1.4.min.js:2
n @ jquery-2.1.4.min.js:2
(anonymous function) @ locallinks_extension.js:16