警报框是系统对象，不受CSS约束。为此，您需要创建一个HTML元素并模仿其
alert()功能。jQueryUIDialogue为您做了很多工作，基本上就像我描述的那样：link。
<!doctype html><html lang="en"><head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>jQuery UI Dialog - Default functionality</title> <link rel="stylesheet" href="//pre.jquery.com/ui/1.12.1/themes/base/jquery-ui.css"> <link rel="stylesheet" href="/resources/demos/style.css"> <script src="https://pre.jquery.com/jquery-1.12.4.js"></script> <script src="https://pre.jquery.com/ui/1.12.1/jquery-ui.js"></script> <script> $( function() { $( "#dialog" ).dialog(); } ); </script></head><body><div id="dialog" title="Basic dialog"> <p>This is the default dialog which is useful for displaying information. The dialog window can be moved, resized and closed with the 'x' icon.</p></div></body></html>
