为什么代码在课程里显示正常，在Dreamweaver点击就弹不出对话框？
代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<script type="text/javascirpt">
function rec(){
var score;
score =prompt("成绩");
if(score>=90)
{
document.write("真棒！");
}
else if(score>=75)
{
document.write("不错呦");
}
else
{
document.write("要努力了！");
}
}
</script>
</head>
<body>
<input name="button" type="button" onClick="rec()" value="点击我，对成绩做评价!" />
</body>
</html>
