9.数组length
<![CDATA[
<script type="text/javascript">
var arr=[1,2,3,4,5,6,7,8,9];
var arr2=[];
arr2[20]='abc';
/*
使用下标赋值，前面不存在的元素填充为undefined
*/
var alen =arr.length;
var alen2=arr2.length;
document.write(alen+'<br>');<!--结果输出在页面中document为文档节点-->
//var arr=[1,2,3,4,5,6,7,8,9];
document.write(arr2.length);
for (var i in arr2){
document.write(arr2[i]+'<br>');<!--结果输出在页面中document为文档节点-->
};
document.write('<hr>');
for(var i=0;i<alen2;i++){
document.write('arr2['+i+']='+arr2[i]+'<br>');
};
document.write('<hr>');
document.write('测试数组赋值<br>');
var narr =new Array();//首字母大写
for (var i in narr){
document.write(narr[i]+'<br>');<!--结果输出在页面中document为文档节点-->
};
narr[0]="abc";
narr[1]=46;
narr[3]='like';
for (var i in narr){
document.write(narr[i]+'<br>');<!--结果输出在页面中document为文档节点-->
};
for(var i=0;i<narr.length;i++){
document.write('narr['+i+']='+narr[i]+'<br>');
};
</script>
]]>