In JavaScript, there is no built-in function called sleep() to pause the execution of a program for a specified amount of time. However, you can use the setTimeout() function to achieve a similar effect.

To insert an item into an array at a specific index in JavaScript, you can use the splice() method. The splice() method allows you to modify the original array by adding, removing or replacing elements.

To remove a specific item from an array in JavaScript, you can use the splice() method. The splice() method modifies the original array and returns an array containing the removed items.

To validate an email address in JavaScript, you can use a regular expression (regex) pattern.

You can use the ::placeholder pseudo-element in CSS to target the placeholder text of an HTML5 input and change its color.

No, there is no parent selector in CSS. CSS selectors allow you to select elements based on their tag name, class, and id, as well as their attributes and their relationship to other elements in the DOM (Document Object Model). However, there is no way to select an element based solely

To select the first element with a specific class in CSS, you can use the :first-of-type pseudo-class in combination with the class selector.