JS中的for循环

for...in... #循环对象的信息

for (var propName in window) {
              document.write(propName);
}

for 与 while

    var count = 10;
    for (var i=0; i < count; i++){
        alert(i);
    }
    /* The preceding is the same as:
    var count = 10;
    var i = 0;
    while (i < count){
        i++;
    }
    */