Execute Script after Specified Delay Using JavaScript

Executing a script after a specific delay is a common task in JavaScript. To do this, you can leverage the setTimeout() method.

Unlike jQuery's delay() or wait(), setTimeout() accepts a function as its first parameter. This function is what you want to execute after the delay. The second parameter specifies the delay in milliseconds.

Using Named Functions for Delay

The following code demonstrates how to call a function with a delay using a named function:

function myFunction() {
  // Code to execute after the delay
}

setTimeout(myFunction, 2000); // Execute "myFunction" after 2 seconds

Using Anonymous Functions for Parameter Passing

If you want to call a function with a parameter, you can use an anonymous function:

var a = "world";
setTimeout(function(){alert("Hello "   a)}, 2000);

However, this can lead to issues if the value of a changes before the delay expires. To preserve the original value, you can wrap the anonymous function in another function that takes a as an argument:

function callback(a){
    return function(){
        alert("Hello "   a);
    }
}

var a = "world";
setTimeout(callback(a), 2000);