Use Jquery to modify the default selection of page selecte labels

Provides a variety of official and user-released code examples. For code reference, you are welcome to exchange and learn the general implementation of the default options for selecte labels based on Jquery.
In WEB development, the most basic and most commonly used is the addition, deletion, modification, and query of databases. Only a small part of modifications are often made, therefore, we usually fill in the form with the previous content and then display it to the user for modification.
When filling in the default content, we often use value =" "Method, for example: ' />But it is not that simple for the select tag because it does not have the value attribute. We usually use code similar to the following: $v){?> > In this way, as long as we make similar output and judgment on each select label, we can meet our requirements, but it is a little complicated and not easy to maintain. Below is a method implemented using Jquery:
First, when the select tag is output, the default value is saved to the custom default (others can also be) attribute: $v){?> Then, in the head of the document orImport the jquery library file before: