js ip数字与字符转换

function ipToNumber(ip) {  
	var numbers = ip.split(".");  
	return parseInt(numbers[0])*256*256*256 +   
	parseInt(numbers[1])*256*256 +   
	parseInt(numbers[2])*256 +   
	parseInt(numbers[3]);  
}  

function numberToIp(number) {  
	return (Math.floor(number/(256*256*256))) + "." +   
	(Math.floor(number%(256*256*256)/(256*256))) + "." +   
	(Math.floor(number%(256*256)/256)) + "." +   
	(Math.floor(number%256));  
}