小仙女-js基础精华

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js基础精华

1.eval函数应用

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function test2()
{
var b ="var a=3";
eval(b);
alert(a);
//str = "alert('this is a orange')";
//eval(str);
}

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2.解码与转码

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/*
escape字段转码
*/
<script>
function tryescape()
{
var a = document.getElementById("escape");
var b = document.getElementById("textunescape").value=escape(a.value);

}
/*
unescape字段解码
*/
function trytextunescape()
{
var a = document.getElementById("escape");
var b = document.getElementById("textunescape").value=unescape(a.value);

}
</script>
<body>
<h2>escape()函数</h2>
<input type ="text" id="escape">
显示：<input type ="text" id="textunescape">
<input type="button" value="点我" onclick="escape()"/>
<body>

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3.获取表单属性

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/*
获取表单属性
*/
function getForElements()
{
var loginForm=document.loginForm;
var array=loginForm.elements;
var message="该表单";
for(var i=0;i<array.length;i++){
message+="第"+（i+1）+"个表单域：type="+array[i].type+",id="+array[i]+id+",
name="+array[i].name+",value="+array[i].value+"<br>";
}
document.getElementById("formElements").innerHTML=message;
}

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4.死链接

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function checkForm(){var flag=true;var longinForm=document.forms[0];var email=loginForm.elements[0].value;var pwd=loginForm.elements[1].value;if(email==""){alert("sorry,no email");flag=false;}if(pwd==""){alert("sorry,no paw");flag=false;}if(flag==true){loginForm.submit();}}<body><h1 align="center">form表单对象的onsubmit事件</h1>    <form id="loginForm" name="loginForm" method="get"action="http://www.baidu.com">邮箱：<input type="text" id="email" name="email"/><br>密码：<input type="password" id="pwd" name="pwd"/><br><input type="button"  value="登录 "onclick="checkForm()"/><input type="reset"  value="重置" /></form></body>