function str_replace(Search, Replace, Subject){

  if ((Subject == null) || (Search == null)) return null;
  if ((Subject.length == 0) || (Search.length == 0)) return Subject;
  if ((Replace == null) || (Replace.length == 0)) Replace = "";

  var LengthSearch = Search.length;
  var LengthReplace = Replace.length;
  var Pos = Subject.indexOf(Search, 0);

  while (Pos >= 0){
    Subject = Subject.substring(0, Pos) + Replace + Subject.substring(Pos + LengthSearch);
    Pos = Subject.indexOf(Search, Pos + LengthReplace);
  }
 
  return Subject;
}

function strstr(Haystack, Needle){
  if ((Haystack == null) || (Needle == null)) return null;
  if ((Haystack.length == 0) || (Needle.length == 0)) return null;
  if(typeof Haystack.indexOf == 'undefined') return false;
  var result = Haystack.indexOf(Needle);
  if(result<0) return false;
  return true;
}

function rtrim(string){
  if(typeof string == 'undefined' || 
    typeof string.substr == 'undefined') return string;
  var lastCharacter = string.length - 1; 
  while(string.substr(lastCharacter)==' '){
    
    if(string.substr(lastCharacter)!=' ' || lastCharacter<=0) break;
    
    string = string.substr(lastCharacter);
    lastCharacter = string.length - 1;
  }
  
  return string;

}

function ltrim(string){
  if(typeof string == 'undefined' || 
    typeof string.substr == 'undefined') return string;
  while(string.substr(0, 1)==' '){
    
    if(string.substr(0, 1)!=' ' || string.length<=0) break;
    
    string = string.substr(1);
  }
  
  return string;
}

function trim(string){
  
  ltrim(string);
  rtrim(string);
  
  
  return string;
}

function urlEncode(str) {
  if(encodeURI) return encodeURI(str);
  return escape(str);
}