代码编辑器：
x
1
2
<meta charset="utf-8">3
<link href="/static/next/css/tryit.css?v=2017082407" rel="stylesheet"/> 4
<script>5
function ChangeOpacity(x)6
{7
// Return the text of the selected option8
var opacity=x.options[x.selectedIndex].text;9
var el=document.getElementById("p1");10
if (el.style.opacity!==undefined)11
{el.style.opacity=opacity;}12
else13
{alert("Your browser doesn't support this example!");}14
}15
</script>16
<p id="p1">Select a value from the list below, to change this element's opacity!</p>17
<select onchange="ChangeOpacity(this);" size="5">18
<option />0