What are some benefits of using jQuery?

You should be able to vocalize the benefits of jQuery. It is lightweight, open source, has lots of plugins, and jQuery has a great community and user support. It is incredibly good at matching CSS selectors, it supports chains of actions, and it has many useful AJAX methods. These are just some basic reasons. You [...]

Explain the difference between synchronous and asynchronous JS request?

Most importantly, synchronous request blocks JavaScript engine until the interaction with the server is complete. The user cannot click away, cancel request, or go to another tab during this time. It is bad for user experience and that is why we have AsynchronousJAX. (AJAX)

Explain briefly the difference between normal array and associative arrays?

This kind of a question could be rephrased as “explain the difference between a['one']=’dog’ and a[one]=’dog’” because the main difference between a normal array in JavaScript and associative arrays is that associative arrays use Strings instead of Integer numbers as index. But this is also kind of a trick question as JavaScript does not support [...]

What is the difference between undefined value and null value?

In JavaScript, undefined means that a value has been declared but has not yet been assigned a value, such as null, which can be assigned to a variable as a representation of no value. If a value is null, it was assigned programmatically, as JavaScript never sets a value to null on its own. Also, [...]

What is the main difference between window.onload and onDocumentReady?

Both functions are used to perform tasks when the page is loaded in the browser but they have important differences. Most importantly, “window.onload” will execute code when browser has loaded the DOM tree and all other resources like images, objects, etc, while onDocumentReady allows you to execute code when only the DOM tree has been [...]