SOURCE

function writeDocument(variable){
    document.write(variable+"<br/>")
}
var arr=["HTML","CSS","XXX"];
writeDocument(arr[2]);
writeDocument(arr);
//数组的赋值
arr[2]="HHH";
writeDocument(arr);
arr[3]="XXX";
writeDocument(arr);
arr[5]="ccc";
writeDocument(arr);
arr[9]="yyy";
writeDocument(arr);