js判断数据类型如判断是否为数组是否为字符串等等

1 判断是否为数组类型
2 判断是否为字符串类型
3 判断是否为数值类型
4 判断是否为日期类型
5 判断是否为函数
6 判断是否为对象

1 判断是否为数组类型

<script type="text/javascript"> 
//<![CDATA[ 
var a=[0]; 
document.write(isArray(a),'<br/>'); 
function isArray(obj){ 
return (typeof obj=='object')&&obj.constructor==Array; 
} 
//]]> 
</script>

2 判断是否为字符串类型

<script type="text/javascript"> 
//<![CDATA[ 
document.write(isString('test'),'<br/>'); 
document.write(isString(10),'<br/>'); 
function isString(str){ 
return (typeof str=='string')&&str.constructor==String; 
} 
//]]> 
</script>

3 判断是否为数值类型

<script type="text/javascript"> 
//<![CDATA[ 
document.write(isNumber('test'),'<br/>'); 
document.write(isNumber(10),'<br/>'); 
function isNumber(obj){ 
return (typeof obj=='number')&&obj.constructor==Number; 
} 
//]]> 
</script>

4 判断是否为日期类型

<script type="text/javascript"> 
//<![CDATA[ 
document.write(isDate(new Date()),'<br/>'); 
document.write(isDate(10),'<br/>'); 
function isDate(obj){ 
return (typeof obj=='object')&&obj.constructor==Date; 
} 
//]]> 
</script>

5 判断是否为函数

<script type="text/javascript"> 
//<![CDATA[ 
document.write(isFunction(function test(){}),'<br/>'); 
document.write(isFunction(10),'<br/>'); 
function isFunction(obj){ 
return (typeof obj=='function')&&obj.constructor==Function; 
} 
//]]> 
</script>

6 判断是否为对象

<script type="text/javascript"> 
//<![CDATA[ 
document.write(isObject(new Object()),'<br/>'); 
document.write(isObject(10),'<br/>'); 
function isObject(obj){ 
return (typeof obj=='object')&&obj.constructor==Object; 
} 
//]]> 
</script>