<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>异常处理</title>
<script>
//try catch throw
var txt="";//定义空的字符串
function message(){//方法
try{//要执行的代码块
allert("message");//误写的方法
}catch(err){//捕捉异常
txt="There is an error in current page!\n\n";//末尾换行
txt+="Error:"+err.message+"\n\n";//尾添加拼接错误信息
txt+="Please click 'OK' to continue!\n\n";
alert(txt);//弹出错误信息
}
}
</script>
</head>
<body>
<h3>结果:</h3>
<input type="button" value="message" onclick="message()" />
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>异常处理</title>
<script>
function validateNumbers(){
var nums=document.getElementById("Numbers").value;
var errMess=document.getElementById("errMess");
try{
if(nums==""||nums==undefined) throw "is empty";//判断满足,则抛出异常
else if(isNaN(nums)) throw "is not number";
else if(nums<5) throw "is too low";
else if(nums>10) throw "is too high";
else errMess.innerHTML="";//正常情况下清空错误信息
}catch(err){
errMess.innerHTML="Error : "+err+"!";
}
}
</script>
</head>
<body>
<h3>结果:</h3>
<p id="tips" style="color: gray;">Please input a number between 5 and 10 :</p>
<input type="text" name="Numbers" id="Numbers" />
<input type="button" onclick="validateNumbers()" value="Validate" />
<p id="errMess" style="color: red;"></p>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>异常处理</title>
<script>
function validateRequired(x,txt){
with(x){
if(value==null || value==""){
alert(txt);
return false;
}else{
return true;
}
}
}
function validateForms(form){
with(form){
if(validateRequired(email,"Email must be filled out !")==false){
{
email.focus();
return false;
}
}
}
}
</script>
</head>
<body>
<h3>结果:</h3>
<form>
</form>
</body>
</html>
