checkbox validation error

checkbox validation error

hi guys
how do i validate a checkbox, the code below gives errors

error message is 

 Uncaught TypeError: "#SaC_Check".is is not a function


Ehi

  1.    $("#SaC").click(function (e) {

  2.                 if (!('#SaC_Check').is(':checked')) {
  3.                     alert("Please click the checkbox to agree to our Terms & Conditions !");
  4.                 };
  5.             });