Jquery if in page - Javascript

Introduction

In this article, we will learn about using jQuery to check if an element exists on a webpage using JavaScript. We will explore different scenarios that programmers encounter while working with conditional statements in jQuery.

Checking if an Element Exists in the Page

There are several ways to check if an element exists in a page using jQuery. Let's go through each approach:

1. Using the length property

if ($('selector').length) {
    // Element exists in the page
} else {
    // Element does not exist in the page
}

Explanation:

• The $('selector').length returns the number of elements matched by the selector.
• If the length is greater than 0, it means that the element exists in the page. Otherwise, it doesn't.

2. Using the is() method

if ($('selector').is('*')) {
    // Element exists in the page
} else {
    // Element does not exist in the page
}

Explanation:

• The is() method checks if any element in the matched set matches the selector.
• If it returns true, it means that the element exists in the page. Otherwise, it doesn't.

3. Using the exists() function

jQuery.fn.exists = function () {
    return this.length > 0;
};

if ($('selector').exists()) {
    // Element exists in the page
} else {
    // Element does not exist in the page
}

Explanation:

• Custom exists() function is created as a jQuery plugin.
• The function checks if the length of the matched set is greater than 0.
• If it returns true, the element exists. Otherwise, it doesn't.

4. Using the length property directly

if ($('selector')[0]) {
    // Element exists in the page
} else {
    // Element does not exist in the page
}

Explanation:

• Accessing the first element in the matched set using [0] will return the element if it exists. Otherwise, it will return undefined.

Conclusion

Checking if an element exists on a webpage is a common task in web development. By using jQuery, we have explored various techniques to accomplish this using JavaScript. Whether you choose to use the length property, the is() method, a custom exists() function, or accessing the first element directly, you now have the knowledge to effectively check if an element exists using jQuery.