JavaScript去除字符串前后的空格

function Trim(str) //去除字符串首尾空格{if(typeof(str)!="string"){ //必须是字符串才能进行去除首位空格的操作return;}if(str.length==0){ //空字符串原样返回return str;}var leftIndex=0; //用来寻找字符串左端空格的游标while(leftIndex<str.length){if(str[leftIndex]==" ")leftIndex++;elsebreak;}if(leftIndex==str.length)return "";if(leftIndex!=0)str=str.substring(leftIndex,str.length);var rightIndex=str.length-1; //用来寻找字符串右端空格的游标while(rightIndex>0){if(str[rightIndex]==" "){rightIndex--;}elsebreak;}if(rightIndex!=str.length-1){str=str.substring(0,rightIndex+1);}return str;}