去掉字符串前后的空格的函数！

[wuxing]

//去掉字符串前后的空格函数
function trimString(inString) {
var outString;
var startPos;
var endPos;
var ch;

// where do we start?
startPos = 0;
ch = inString.charAt(startPos);
while ((ch == " ") || (ch == "\b") || (ch == "\f") || (ch == "\n") || (ch == "\r")
|| (ch == "\n")) {
startPos++;
ch = inString.charAt(startPos);
}

// where do we end?
endPos = inString.length - 1;
ch = inString.charAt(endPos);
while ((ch == " ") || (ch == "\b") || (ch == "\f") || (ch == "\n") || (ch == "\r")
|| (ch == "\n")) {
endPos--;
ch = inString.charAt(endPos);
}

// get the string
outString = inString.substring(startPos, endPos + 1);

return outString;
}
//但是有个问题，当你只输入空格的时候，使用trimString（string）＝＝“”；想判断字符串不能为空和字符串，他就不能起到作用。请那位高手更改一下！