Definition and usage examples of jQuery callback function_jquery

The examples in this article describe the definition and usage of jQuery callback functions. Share it with everyone for your reference. The specific analysis is as follows:

Callback functions are widely used in jQuery code. It is very necessary to have a precise understanding of them. Here is a brief introduction to this method through examples.

The code example is as follows:

Use the callback function to pop up a prompt box when all divs are hidden.

Copy code The code is as follows:

Click to see the effect

The above code runs very well and is in order. In many practical applications, it is often hoped that the code will complete an action before doing another action.
The code seems to have the same effect as the above code, but the result is not what we expected. Instead, a prompt box pops up first, and then the div element is hidden. This does not mean that slideUp() does not start executing.

Copy code The code is as follows:

Click to see the effect

The following is a simple and popular summary of what a callback function is. Look at the following code:

Copy code The code is as follows:

function a(){alert("I am a function")}
a();

The above is the most common way to call a function. It is called directly by the function implementation. However, the callback function is not like this. It passes its own address as a parameter to another function. When a specific event occurs, The callback function will be called using the callback function address passed as a parameter. Take the code using the callback function above as an example. It passes the address of the function function as a parameter to the slideUp() method. When the slideUp() action is completed, the function function will be called through the passed address parameter.

I hope this article will be helpful to everyone’s jquery programming design.