js 对象属性遍历

function 对象属性遍历(){

var obj = {x:1,y:2,c:3};
for (var name in obj){
alert ( obj[name] )
}

}

function  数组(){

var 数组=[1,2,3,[1,2,4,5,7,8],4,5];   //数组嵌套数组
var 数组2=[
{x:100},
2,
[7,8,9],
function(){
return 999;
}(),
"abc"
]

var arr =new Array(10);
arr[20]=100
alert(arr)

};

function  test(){

   //数组嵌套数组

var str ="yiyuyan";
return str.charAt(6)           //alert(字符串[5]);

};

function  test(){

   //数组嵌套数组

var arr =[1,2,3,4,5,6,7,8,9,10] , sum =0;
for(var i=0;i<arr.length;i++){
sum +=arr[i];
}

alert (sum)  ;         //alert(字符串[5]);

};