Advanced Interview Questions
The following will cover the senior web developer interview questions but I suggest you go through them even if you are a fresher or an intermediate web developer candidate
0- What are the types of popup boxes present in JavaScript?
There are three types of dialog boxes, which are used in JavaScript:
| type | usage |
|---|---|
| alert | Presents users with a message and an OK button |
| Confirm | Gives the users a window with OK and Cancel buttons |
| Prompt | Shows the user input, alongside OK and Cancel buttons |
Advanced Interview Questions
The following Blog will cover the senior web developer interview questions but I suggest you go through them even if you are a fresher or an intermediate web developer candidate
What are the types of popup boxes present in JavaScript?
1- There are three types of dialog boxes, which are used in JavaScript
The <window.onload> event is not called until a page is completely loaded with the entire styling from CSS and images. The event does add a bit of delay when rendering a web page.
With the <onDocumentReady> event, it will wait only till the DOM is initialized and will begin the event action. This ensures to reduce any delays in actions.
2- How is type conversion handled in JavaScript?
JavaScript supports automatic type conversion. Since it is weakly typed, you can pass a function as an argument into another function easily.
This ensures that there are no errors or data type-associated warnings as values get converted to the required data type automatically.
3- What is the meaning of the scope of a variable in JavaScript?
Scope refers to the accessibility of functions and underlying variables in the running environment. There are two scopes supported in JavaScript:
- Local scope: Here, values and functions declared inside the same function function can only be accessed within that function and not outside it. Consider the following example:
// Code present here cannot use localVariable
function myFunction() {
var localVariable = "This is a local variable";
// Code present here can use localVariable
}
- Global scope: If a variable is declared as global, it can be accessed from anywhere in the application. Consider the following example:
var globalVariable = "This is a Global variable";
// Code present here can use globalVariable
function myFunction() {
// Code present here can also use globalVariable
}
4- How are comments used in JavaScript?
JavaScript supports two types of comment insertion in the code. Single-line comments and multi-line comments.
Single-line comment: “//” is used for single-line comment insertion
Example:
//This is a single-line comment
Multi-line comment: `/**/” is used to add multi-line comments
Example:
js
/* This
is a
multi-line
comment*/
Coming to the next set of interview questions for web developers, here is a common question for JavaScript.
5- What are undefined and undeclared variables in JavaScript?
- Variables that have been declared already but not initialized are known as undefined variables.
On the other hand, if a variable is being used in a program without being declared, then it is considered as an undeclared variable.
Consider the following example:
js
var undefVar;
alert(undefVar); // undefined variable
alert(notDeclared); // accessing an undeclared variable
6- What is the method used to submit forms in JavaScript?
Forms can be submitted easily in JavaScript by calling the following method:
document.forms[0].submit();
Here, Zero 0 denotes the index of the form.
7- Why is keyword used a lot in JavaScript?
The <this> keyword is used to access the current object present in a program. This object resides inside a method, and the keyword is used for referencing the corresponding variable or object.
8- What is the use of the ‘defer’ attribute in JavaScript?
The attribute is used as a boolean type attribute. It is used to delay the execution of the JavaScript code on a web page until the parser completely loads and initializes the page.
Example:
<script src="/example.js" defer></script>
9- How can you prioritize SEO, maintainability, performance, and security in a web application?
This is a commonly asked question in a Web Development interview. Here, the interviewer is trying to assess your understanding of the working environment in the firm you’ve applied for.
If it is a large firm, then security will get higher priority over SEO. Whereas, if it is a publication firm, SEO gets the preference. A little groundwork about the company should help you answer this question.
The next web developer interview question we will look at is regarding jQuery. Check it out.
10- What is the result if a jQuery Event Handler returns false?
If the jQuery Event Handler returns a boolean false value, it simply means that the event will not execute further and will halt the execution for the particular action it is associated with.
11- What is the use of the each() function in jQuery?
The each() function in jQuery is used to iterate over a set of elements. A function can be passed to the each() method. This will result in the execution of each of the events for which the object has been called.
12- What is pair programming?
- Pair programming is a scenario where you will be working closely with a colleague on the project, and this is done to help solve the problems at hand. If the development scenario is fast-paced, Agile development might not work efficiently. The interviewer asks this question to see if you can work with other people easily and effectively.
12- What is the use of the $() function in jQuery?
The $() function is used as a wrapper to wrap objects into their jQuery counterparts. This is done to give users the ability to call any method that is defined for the jQuery object.
Note: Selectors can also be passed to the $() function, resulting in the output of a jQuery object that contains matched DOM elements.
13- What are the advantages of using a content delivery network (CDN) in jQuery?
CDNs are widely used in jQuery as they offer an ample number of advantages for users.
CDNs cause a significant reduction in the load for the server.
They provide large amounts of savings in the bandwidth.
jQuery frameworks load faster due to optimizations.
CDNs have a caching ability that adds to quicker load times.
14- List out the advantage of HTTP/2 as compared with HTTP 1.1?
The advantage of HTTP/2 compared to HTTP/1.1 is
- HTTP headers data compression
- Server push technologies
- Over a single TCP connection parallel loading of page elements
- Prioritization of request
15- What are the types of CDNs supported in jQuery?
There are two widely used CDNs with jQuery:
Microsoft: Used to load from jQuery AJAX CDN
Google: Used to load jQuery from the Google libraries API
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Top comments (1)
The post is good but some titles are incomplete . Maybe is a code in title thing idk but hopes it help.