相比vbscript，javascript在字符串处理方面已经很强大了，但是偏偏缺少去除字符串前后空格的trim方法。

//clear the right and left space
function trim(s){
return trimRight(trimLeft(s));
}

//clear the left space
function trimLeft(s){
if(s == null) {
return "";
}
var whitespace = new String(" \t\n\r");
var str = new String(s);
if (whitespace.indexOf(str.charAt(0)) != -1) {
var j=0, i = str.length;
while (j < i && whitespace.indexOf(str.charAt(j)) != -1){
j++;
}
str = str.substring(j, i);
}
return str;
}

//clear the right space
function trimRight(s){
if(s == null) return "";
var whitespace = new String(" \t\n\r");
var str = new String(s);
if (whitespace.indexOf(str.charAt(str.length-1)) != -1){
var i = str.length - 1;
while (i >= 0 && whitespace.indexOf(str.charAt(i)) != -1){
i--;
}
str = str.substring(0, i+1);
}
return str;
}

http://alany.blog.51cto.com/6125308/1658938