代码如下：
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <script src="../../static/js/jquery.js"></script> </head> <body> <select id="test"> <option value="1">1</option> <option value="2">2</option> <option value="3">3</option> <option value="4">4</option> <option value="5">5</option> <option value="6">6</option> </select> <script> var id = "3"; $("#test").val(id); </script> </body> </html>
如图：
原文：https://www.cnblogs.com/fuckingPangzi/p/9932756.html