// JavaScript Document
//去除字符串左右空格
function trim(string){
	var str_start	= 0;
	var str_end		= string.length;
	var c = " ";
	while(str_start < str_end){
		if(c != string.substr(str_start,1)){
			break;
		}
		str_start = str_start + 1;		
	}
	while(str_end > str_start){
		if(c != string.substr(str_end-1,1)){
			break;
		}
		str_end--; 
	}	
	return string.substring(str_start,str_end);
 }