jquery $ (document). The difference between ready () and Window.onload

1. Execution Time

Window.onload must wait until all the elements of the page that include the picture have been loaded before they can be executed.
$ (document). Ready () is executed when the DOM structure is drawn and does not have to wait for the load to complete.

2. Different writing numbers

Window.onload cannot write multiple at the same time, if there are multiple window.onload methods, only one
$ (document). Ready () can be written multiple at the same time and can be executed

3. Simplified notation

Window.onload No simplified notation
$ (document). Ready (function () {}) can be simply written as $ (function () {});

$ (document). Ready (function () {
...
});

This time, do not have to wait for all the JS and pictures loaded, you can execute some methods, but sometimes, must wait for all the elements are loaded, before you can execute some methods, for example, some pictures or what other aspects have not loaded well, this time, click on some buttons, Will cause an unexpected situation, this time,

Need to use:

$ (window). Load (function () {
...
});

The following code does not execute correctly

window.onload = function (){    alert(“第一个”); }; window.onload = function (){    alert(“第二个”); };

The result outputs only the second one can write multiple
The following code executes correctly:

$(document).ready( function (){    alert(“Hello World”); }); $(document).ready( function (){    alert(“Hello again”); }); Results are output twice

jquery $ (document). The difference between ready () and Window.onload