==小例子1
==25 26 27课
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
<script>
function myfun(){
try{
var e=document.getElementById("demo2").value;
if(e=="") throw "值为空了";
if(isNaN(e)) throw "非数字";
if(e>10) throw "大于10了";
}
catch(err){
var y= document.getElementById ("mess2");
y.innerHTML ="错误:" + err + "。";
}
}
</script>
</head>
<body>
<h1>我的第一个查询</h1>
<p>请输出一个 5 到 10 之间的数字:</p>
<input id ="demo2" type="text">
<button type="button" onclick="myfun()">请输入数字</button>
<p id="mess2"></p>
</body>
</html>