There's nothing wrong with the way the code was written before, I'm just submitting my condensed versions to the public.

//Author: Phillip Roberts - phillroberts@yahoo.com
//Released under GNU General Public License : http://www.gnu.org/copyleft/gpl.html


//@Left equivalent
function strLeft(sourceStr, keyStr){
return (sourceStr.indexOf(keyStr) == -1 | keyStr=='') ? '' : sourceStr.split(keyStr)[0];
}

//@Right equivalent
function strRight(sourceStr, keyStr){
idx = sourceStr.indexOf(keyStr);
return (idx == -1 | keyStr=='') ? '' : sourceStr.substr(idx+ keyStr.length);
}

//@RightBack equivalent
function rightBack(sourceStr, keyStr){
arr = sourceStr.split(keyStr);
return (sourceStr.indexOf(keyStr) == -1 | keyStr=='') ? '' : arr.pop()
}

//@LeftBack equivalent
function leftBack(sourceStr, keyStr){
arr = sourceStr.split(keyStr)
arr.pop();
return (keyStr==null | keyStr=='') ? '' : arr.join(keyStr)
}

//@Middle equivalent
function middle(sourceStr, keyStrLeft, keyStrRight){
return strLeft(strRight(sourceStr,keyStrLeft), keyStrRight);
}