2.12.ECMAScript--运算符
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2.12.ECMAScript--运算符
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<!DOCTYPE HTML>
<html lang="en-US">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<script type="text/javascript">
/*
alert( 1988 == "1988");//沒有比較類型所以返回true
alert( 1988 === "1988");//類型比較返回false
*/
/*
var o = new Object;
o.name = "David";
alert(o.name); //輸出 "David"
delete o.name;
alert(o.name); //輸出 "undefined"
*/
/*
//與
document.write( 10 > 1 && 10 > 2);
document.write("<br/>");
//或
document.write( 10 < 1 || 10 < 2);
document.write("<br/>");
//非（取反）
document.write( 10 != 100);
document.write("<br/>");
*/
//驗證表單
function checkChange(){
var username = document.getElementById("username");
if(username.value == "admin" || username.value == "xiaozhanga4"){
alert("恭喜你," + username.value );
}else{
alert("用戶名不能為空");
}
}
</script>
<form action="" method="post">
<input type="text" id="username" name="username"/>
<input type="submit" value="submit" onclick="checkChange();"/>
</form>
</body>
</html>
<html lang="en-US">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<script type="text/javascript">
/*
alert( 1988 == "1988");//沒有比較類型所以返回true
alert( 1988 === "1988");//類型比較返回false
*/
/*
var o = new Object;
o.name = "David";
alert(o.name); //輸出 "David"
delete o.name;
alert(o.name); //輸出 "undefined"
*/
/*
//與
document.write( 10 > 1 && 10 > 2);
document.write("<br/>");
//或
document.write( 10 < 1 || 10 < 2);
document.write("<br/>");
//非（取反）
document.write( 10 != 100);
document.write("<br/>");
*/
//驗證表單
function checkChange(){
var username = document.getElementById("username");
if(username.value == "admin" || username.value == "xiaozhanga4"){
alert("恭喜你," + username.value );
}else{
alert("用戶名不能為空");
}
}
</script>
<form action="" method="post">
<input type="text" id="username" name="username"/>
<input type="submit" value="submit" onclick="checkChange();"/>
</form>
</body>
</html>
轉載于:https://www.cnblogs.com/xiaozhanga4/archive/2012/03/15/2398350.html
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