Javascript

使用多个参数，但是不定义参数个数：arguments.length

<script language="javascript">

function testParameters()

{

var params = "";

for(var i=0;i<arguments.length;i++)

{params += " " + arguments[i]; }

alert(params);

}

testParameters("abc",123);

testParameters(123,456,"abc");

</script>


Function:
这两种Function是一样的功能.
var square = new Function("x","y","var sum;sum=x*x + y*y;return sum;");

function square(x,y){

var sum;

sum = x*x + y*y;

return sum;

}

alert(square(2,3);


System function:
encodeURI();
decodeURI();
parseInt(numString,[radix(0x十六进制 0八进制)]);
parseFloat();
isNaN();
escape();
unescape();
eval();链接数据库时可用eval(): such as

eval("alert(persion1."+ x + ");"); x是变量

with语句：

var abc= new a();

with(abc)

{var kk = getMonth();}

in here don't need use var kk=abc.getMonth();

for...in语句：