?????? ???
???? ?????
???? ?? ???? ??? ??? ????. ?? ??? ?? ???(?? ??)? ??? ??? ???? ????? ??? ??? ???? ?????. . ???? ??:
1. ?? ??? ?? ??? ??? ??? ? ??????.
2. ???? ??? ??? ? ???? ???? ?? ?? ?????.
??? ??? Javascript? ?? ??? ??? ?????. ?, ?? ??? ?? ???? ?? ??? ?? ??? ?????. ?? ??? ?? ??? ?? ?? ??, ???? ? ?? ??? ???? ?? ??? ??? ?? ?? ??? ???? ? ????. ??? ?? ?? ? ??? ?? ???? ?? ?? ???? ???? ???? ?????.
???? ???? ???? ?? ??
? ?? ?? ??
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文網(wǎng)(php.cn)</title>
<script type="text/javascript">
function Circle(r) {
this.r = r;
}
Circle.PI = 3.14159;
Circle.prototype.area = function() {
return Circle.PI * this.r * this.r;
}
var c = new Circle(1.0);
alert(c.area());
</script>
</head>
<body>
</body>
</html>??? ?? ??? ??? ?? ??? ??? ? ?? ??? ??? ????.
? ?? ?? ??
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文網(wǎng)(php.cn)</title>
<script type="text/javascript">
var Circle = function() {
var obj = new Object();
obj.PI = 3.14159;
obj.area = function( r ) {
return this.PI * r * r;
}
return obj;
}
var c = new Circle();
alert( c.area( 1.0 ) );
</script>
</head>
<body>
</body>
</html>? ?? ??? ??? ???? ??? ??? ??? ???? ????.
? ?? ?? ??
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文網(wǎng)(php.cn)</title>
<script type="text/javascript">
var Circle = new Object();
Circle.PI = 3.14159;
Circle.Area = function( r ) {
return this.PI * r * r;
}
alert( Circle.Area( 1.0 ) );
</script>
</head>
<body>
</body>
</html>? ??? ?? ? ?????, ? ??? ?? ?? ?? ??? ??? ???? ???? ????.
??? ? ?? ??
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文網(wǎng)(php.cn)</title>
<script type="text/javascript">
var Circle={
"PI":3.14159,
"area":function(r){
return this.PI * r * r;
}
};
alert( Circle.area(1.0) );
</script>
</head>
<body>
</body>
</html>? ??? ????? ???? ?? ?????. var obj = {}? ? ??? ???? ????
Javascript ???? ??
?? ???? ???? ?? ?? ? ? ????. ?? ??, ?? ?? ?? ???? ?????? ? ???, ??? ?? ???? ???? ???? ?? ???? ??? ?? ???? ??????.
1. ?? ?? ?? ??
2. ?? ??
3. ?? ??? ? ??
JavaScript ?? ???? ??? ?? ??? ??? ? ????.
?? JavaScript??? ?? ??? ? ?? ??? ???? ? ????.
JavaScript? ?? ??? ?????. ??? ??? ?? ??? ?? ??? ??? ? ????.
? ??? ?? ?? plus()? ?? ??? ??? ??? ???? ? ????.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文網(wǎng)(php.cn)</title>
</head>
<body>
<p id="demo">0</p>
<script>
document.getElementById("demo").innerHTML = add();
function add() {
var counter = 0;
function plus() {counter += 1;}
plus();
return counter;
}
</script>
</body>
</html>???? plus() ??? ???? ? ??? ??? ???? ??? ? ????.
?? counter = 0? ? ?? ????? ?? ???.
???? ??? ?????.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文網(wǎng)(php.cn)</title>
</head>
<body>
<button type="button" onclick="myFunction()">計數(shù)!</button>
<p id="demo">0</p>
<script>
var add = (function () {
var counter = 0;
return function () {return counter += 1;}
})();
function myFunction(){
document.getElementById("demo").innerHTML = add();
}
</script>
</body>
</html>?? ??
?? add? ?? ?? ??? ?? ?? ?? ?????.
?? ?? ??? ? ?? ?????. ???? 0?? ?????. ?? ???? ?????.
add ??? ??? ??? ? ????. ?? ??? ?? ?? ???? ???? ?? ???? ????? ????.
?? JavaScript ????? ???. ??? ?? ??? ?? ? ?? ????.
???? ?? ??? ??? ???? add ???? ???? ??? ? ????.
???? ?? ??? ?? ??? ?? ?? ?? ?? ??? ??? ? ?? ?????.
