By Vishal Basumatary in javascript — Mar 24, 2023

jquery questions and answers

JQuery Questions and Answers

As a web developer, I have frequently used jQuery for various projects. Here are some common questions and answers related to jQuery:

What is jQuery?

jQuery is a fast, small, and feature-rich JavaScript library that simplifies HTML document traversing, event handling, animating, and Ajax interactions for rapid web development.

How to include jQuery in a webpage?

We can include jQuery in a webpage by using a script tag. We can either download the jQuery library and include it in our project or use a CDN to include it. Here is an example:


  <head>
    <script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
  </head>

What are selectors in jQuery?

jQuery selectors are used to select HTML elements in a document. We can use CSS selectors, custom selectors, and basic XPath expressions to select elements. Here is an example:


  // Using CSS selector
  $("p")

  // Using custom selector
  $.expr[':'].containsIgnoreCase = function (n, i, m) {
      return jQuery(n).text().toUpperCase().indexOf(m[3].toUpperCase()) >= 0;
  };
  $("p:containsIgnoreCase('jquery')")

  // Using XPath expression
  $.xpath("//*[contains(text(),'jquery')]");

What is the difference between $(document).ready() and $(window).load() in jQuery?

$(document).ready() function is executed as soon as the DOM is ready, i.e., when the HTML document is loaded and parsed. $(window).load() is executed when the entire page, including all dependent resources like images, is completely loaded.

What are jQuery events?

jQuery events are actions or occurrences that happen in the browser, such as a mouse click, hover, scroll, or keypress. We can attach event handlers to these events using jQuery. Here is an example:


  $("button").click(function(){
    alert("Button clicked");
  });

What is AJAX in jQuery?

AJAX stands for Asynchronous JavaScript and XML. AJAX is a technique for creating fast and dynamic web pages that do not require a page reload every time data is requested. We can use jQuery's AJAX functions like $.ajax(), $.get(), $.post() to make AJAX requests. Here is an example:


  $.ajax({
      url: "ajax.php",
      method: "POST",
      data: { name: "John", age: 30 },
      success: function(result){
          $("#div1").html(result);
      }
  });

Conclusion

jQuery is a powerful and widely used library that simplifies JavaScript coding for web developers. By understanding the basics of jQuery, we can create responsive, dynamic, and interactive web pages with ease.