怎么点击没反应
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>prompt</title>
<script type="text/javascript">
function rec(){
var score;
score=prompt("请输入成绩"，"点此输入");
if(score==null){
document.write("输入错误");
}
if(score>=90){
document.write("很棒!");
}
else if(score>=75){
document.write("很好！");
}
else if(score>=60){
document.write("继续加油");
}
else{
document.write("好好努力");
}
}
</script>
</head>
<body>
<input name="button" type="button" onClick="rec()" value="点击我，对成绩做评价!" />
</body>
</html>
