js恶补1
1.onmouseover和onmouseout的事件对应的HTML标签：
<a>, <address>, <area>, <b>, <bdo>, <big>, <blockquote>, <body>, <button>,
<caption>, <cite>, <code>, <dd>, <dfn>, <div>, <dl>, <dt>, <em>, <fieldset>,
<form>, <h1> to <h6>, <hr>, <i>, <img>, <input>, <kbd>, <label>, <legend>,
<li>, <map>, <ol>, <p>, <pre>, <samp>, <select>, <small>, <span>, <strong>,
<sub>, <sup>, <table>, <tbody>, <td>, <textarea>, <tfoot>, <th>, <thead>,
<tr>, <tt>, <ul>, <var>
2.很简单的try...catch语句：
<caption>, <cite>, <code>, <dd>, <dfn>, <div>, <dl>, <dt>, <em>, <fieldset>,
<form>, <h1> to <h6>, <hr>, <i>, <img>, <input>, <kbd>, <label>, <legend>,
<li>, <map>, <ol>, <p>, <pre>, <samp>, <select>, <small>, <span>, <strong>,
<sub>, <sup>, <table>, <tbody>, <td>, <textarea>, <tfoot>, <th>, <thead>,
<tr>, <tt>, <ul>, <var>
2.很简单的try...catch语句：
<html>
<head>
<script type="text/javascript">
var txt=""
function message()
{
try
{
alert("Welcome guest!")//此处可以故意写错，然后就会执行catch的内容
}
catch(err)
{
txt="本页中存在错误。\n\n"
txt+="错误描述：" + err.description + "\n\n"
txt+="点击“确定”继续。\n\n"
alert(txt)
}
}
</script>
</head>
<head>
<script type="text/javascript">
var txt=""
function message()
{
try
{
alert("Welcome guest!")//此处可以故意写错，然后就会执行catch的内容
}
catch(err)
{
txt="本页中存在错误。\n\n"
txt+="错误描述：" + err.description + "\n\n"
txt+="点击“确定”继续。\n\n"
alert(txt)
}
}
</script>
</head>
<body>
<input type="button" value="查看消息" />
</body>
<input type="button" value="查看消息" />
</body>
</html>
3.带有确认判断和跳转的try...catch语句
<html>
<head>
<script type="text/javascript">
var txt=""
function message()
{
try
{
adddlert("Welcome guest!")
}
catch(err)
{
txt="本页中存在错误。\n\n"
txt+="点击“确定”继续查看本页，\n"
txt+="点击“取消”返回首页。\n\n"
if(!confirm(txt))
{
document.location.href="/index.html"
}
}
}
</script>
</head>
<head>
<script type="text/javascript">
var txt=""
function message()
{
try
{
adddlert("Welcome guest!")
}
catch(err)
{
txt="本页中存在错误。\n\n"
txt+="点击“确定”继续查看本页，\n"
txt+="点击“取消”返回首页。\n\n"
if(!confirm(txt))
{
document.location.href="/index.html"
}
}
}
</script>
</head>
<body>
<input type="button" value="查看消息" />
</body>
<input type="button" value="查看消息" />
</body>
</html>
4.带有throw的异常处理
<html>
<body>
<script type="text/javascript">
var x=prompt("请输入 0 至 10 之间的数：","")
try
{
if(x>10)
throw "Err1"
else if(x<0)
throw "Err2"
else if(isNaN(x))
throw "Err3"
}
catch(er)
{
if(er=="Err1")
alert("错误！该值太大！")
if(er == "Err2")
alert("错误！该值太大！")
if(er == "Err3")
alert("错误！该值不是数字！")
}
</script>
</body>
</html>
<body>
<script type="text/javascript">
var x=prompt("请输入 0 至 10 之间的数：","")
try
{
if(x>10)
throw "Err1"
else if(x<0)
throw "Err2"
else if(isNaN(x))
throw "Err3"
}
catch(er)
{
if(er=="Err1")
alert("错误！该值太大！")
if(er == "Err2")
alert("错误！该值太大！")
if(er == "Err3")
alert("错误！该值不是数字！")
}
</script>
</body>
</html>
5.捕捉错误的onerror，来捕捉网页错误，有三个参数：msg(错误信息)、url(链接地址)和line(发生错误的行)
<html>
<head>
<script type="text/javascript">
onerror=handleErr
var txt=""
function handleErr(msg,url,l)
{
txt="There was an error on this page.\n\n"
txt+="Error: " + msg + "\n"
txt+="URL: " + url + "\n"
txt+="Line: " + l + "\n\n"
txt+="Click OK to continue.\n\n"
alert(txt)
return true
}
<head>
<script type="text/javascript">
onerror=handleErr
var txt=""
function handleErr(msg,url,l)
{
txt="There was an error on this page.\n\n"
txt+="Error: " + msg + "\n"
txt+="URL: " + url + "\n"
txt+="Line: " + l + "\n\n"
txt+="Click OK to continue.\n\n"
alert(txt)
return true
}
function message()
{
adddlert("Welcome guest!")
}
</script>
</head>
{
adddlert("Welcome guest!")
}
</script>
</head>
<body>
<input type="button" value="View message" />
</body>
<input type="button" value="View message" />
</body>
</html>