Here are a few of the JavaScript and jQuery methods which I find useful when debugging my projects.

• JSON.stringify() can be used to inspect objects
• To inspect the value of element attributes like class or id, use .attr() e.g. $('#myelementid').attr('class')
• For an element with multiple classes, you can check if it has a particular class using .hasClass()
• $(selector).length gives the count of the matched elements

… and things to check if code isn’t working as expected

• If jQuery code is unexpectedly failing to have any effect on an element in the document, go back to basics and make sure you have put the call to the code in the document‘s ready event so that it is not called until all the elements are present:
  $(document).ready(function(){
// code
});