JavaScript Interview Questions

JavaScript is one of the most powerful and flexible languages of the web. It is also known as a scripting language, as it interprets the script each time when run. It is often used for client-side web development, which refers to the operations performed by the client in a client-server relationship. JavaScript mainly designed to provide dynamic behavior to most of the websites on the web.

Along with these, JavaScript has many uses such as adding interactivity to the HTML pages, giving a reaction on events, used to validate the data and many more. If you want to know all the features, uses, and tools of JavaScript then go to the JavaScript online interview questions and find the answer to each question of yours. Also, these interview questions will help you to crack the interviews if you are preparing to get the job of web development.

Note: Despite the name, JavaScript and Java are totally different languages. Never consider JavaScript as Java.

    Javascript Vs Java

    JavaScript

    Java

    It is easy to learn

    It is harder to learn than the JavaScript

    It is more fluid type

    It is somewhat rigid

    It is object-oriented programming script language.

    It is an object-oriented programming language

    Its codes are all in the text.

    Its codes need to be compiled.

    Its applications can run on browsers.

    Its application can run in a virtual machine or browser.

    Objects of JavaScript are the prototype based

    Java objects are class-based

    Its program files have an extension of ".js"

    Its program files have an extension of ".Java"

    It needs less space than Java

    It needs more space.

    Pros of Javascript

    Speed: One of the main advantages of using JavaScript is that it is very speedy because it can be work instantly within the client-side browser. JavaScript is unobstructed by the network calls to a backend server until you require outside resources. Moreover, it does not need to have compiled on the client side which is also played a vital role in enhancing its speed.

    Interoperability: Developers are using JavaScript because it can be played nicely with other languages. In comparison with other scripts like PHP and SSI, JavaScript can be added into any web page irrespective of the file extension. Moreover, you can also use JavaScript inside the script in other languages like PHP and Perl.

    Loosely Typed Language: Another astonishing feature of the JavaScript is that it is a loosely typed language which allows the developer to have more control over the code. Moreover, developers also don't need to worried about the function return type, variable type, etc. It doesn't depend on the object as an attribute can be read from any object. Only one function can handle all the types so you don't need function overloading and also, you don't need to worry about the mismatch error in the whole function.

    Maintenance: We know that the update in any language is most important because many new features and tools get advanced with time. To compete with other similar languages, Ecma International updates the JavaScript annually.

    Popularity: Since JavaScript is used everywhere on the web, so developers don't find any difficulty to learn it, as many resources are available on the Internet.

    Special features in function: JavaScript has so many unique features that give it a different look. JavaScript is very flexible as it can accept any type of argument even without declaring. Moreover, it can also return any type of value which is very useful in projects. Another feature of JavaScript is that it can also store the functions as the value of variables. Moreover, these functions can also pass and return as the objects do.

    Cons of Javascript

    Browser Support: It is seen that sometimes the JavaScript is rendered differently by the different browsers. While server-side scripts always give the exact output, but client-side scripts can be a little bit unpredictable. But you don't need to worry much about it. As far as you check your script in all the browser, you are safe.

    Slow Bitwise operation: When you look at the bitwise operation, you may be frustrated. The reason for this is that it converts the operand in 32-bit signed integer and reverse the result to a 64-bit floating point.

    Client-Side Security: It may happen that the codes execute on the computer may get used for malicious purposes. This is considered to be one of the disadvantages of JavaScript.

    Security Issues: JavaScript doesn't possess any type of linker because of the load and go delivery approach. As a result, computational units are all mixed in common global space, which affects a few security issues in some instances.