简单教程
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代码编辑器：
<!DOCTYPE html> <meta charset="utf-8"> <link href="/static/next/css/tryit.css?v=2017082407" rel="stylesheet"/> <script> function ChangeOpacity(x) { // Return the text of the selected option var opacity=x.options[x.selectedIndex].text; var el=document.getElementById("p1"); if (el.style.opacity!==undefined) {el.style.opacity=opacity;} else {alert("Your browser doesn't support this example!");} } </script> <p id="p1">Select a value from the list below, to change this element's opacity!</p> <select onchange="ChangeOpacity(this);" size="5"> <option />0 <option />0.2 <option />0.5 <option />0.8 <option selected="selected" />1 </select> <footer>简单教程，简单编程<br/>Copyright © 简单教程 www.twle.cn</footer>
运行结果：