When does document.ready() get invoked?

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5 Answers

90%

If .ready() is called after the DOM has been initialized, the new handler passed in will be executed immediately.,The .ready() method can only be called on a jQuery object matching the current document, so the selector can be omitted.,$document.ready(fn) will be loaded at the beggining of interactive face when the Dom has "completed" loading...,Code included inside $( document ).ready() will only run once the page Document Object Model (DOM) is ready for JavaScript code to execute.

n = -1;

function ready() {
   document.getElementsByTagName("p")[0].textContent += "ready " + ++n + "\n";
}

$(document).ready(ready);

$(document).ready(function() {
   ready();
   $(document).ready([function() {
         ready()
      },
      function() {
         $(document).ready(function() {
            ready();
            $(document).ready([
               function() {
                  ready()
               },
               function() {
                  ready()
                  if (n === 5) $(document).ready(function() {
                     ready()
                  })
               }
            ]);

         })
      }
   ])
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js">
</script>

<body>
   <p></p>
</body>
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88%

The .ready() method offers a way to run JavaScript code as soon as the page's Document Object Model (DOM) becomes safe to manipulate. This will often be a good time to perform tasks that are needed before the user views or interacts with the page, for example to add event handlers and initialize plugins. When multiple functions are added via successive calls to this method, they run when the DOM is ready in the order in which they are added. As of jQuery 3.0, jQuery ensures that an exception occuring in one handler does not prevent subsequently added handlers from executing.,Miscellaneous Collection Manipulation Data Storage DOM Element Methods Setup Methods ,There is also $(document).on( "ready", handler ), deprecated as of jQuery 1.8 and removed in jQuery 3.0. Note that if the DOM becomes ready before this event is attached, the handler will not be executed.,jQuery offers several ways to attach a function that will run when the DOM is ready. All of the following syntaxes are equivalent:

$(document).ready(function() { // Handler for .ready() called.});
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72%

For example, if our page contains a larger size image, so onload() event will wait till the image is fully loaded. ,We can have multiple document.ready() function in our code but only one body.onload() is allowed.,The document.ready() function will be executed as soon as the DOM is loaded. It will not wait for the resources like images, scripts, objects, iframes, etc to get loaded.,The body.onload() event will be called once the DOM and all associated resources like images got loaded. Basically, onload() will be called when the page has been fully loaded with entire images, iframes and stylesheets, etc.

65%

The ready method is called on the document in the following way:,The ready method allows you to wait for the DOM to be loaded before you add other elements to your HTML file.,Using this method allows time for your DOM to be loaded completely, and then it adds all other elements.,Note: Post jQuery 3.0, this way of calling the ready function is not advisable. Rather you simply call the function as $(function) as the ready method is only called on the current document.

$(document).ready(function);
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75%

on the document element: $(document).ready(handler);,The ready event is fired when the DOM is fully loaded and accesses to elements are safe. The load event, on the other hand, is fired after the DOM and all assets have loaded.,This waits not only for the DOM to be ready for interaction but also for images to be completely loaded (which can take time, depending on the image sizes).,You could also include the domReady library, which has already implemented this solution.

Before jQuery 3.0, the typical usage with a anonymous function looked like this:

$(document).ready(function() {
   // Handler for .ready() called.
});
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