function dateAddExtention(p_Interval, p_Number){ 
 
 
   var thing = new String(); 
    
    
   //in the spirt of VB we'll make this function non-case sensitive 
   //and convert the charcters for the coder. 
   p_Interval = p_Interval.toLowerCase(); 
    
   if(isNaN(p_Number)){ 
    
      //Only accpets numbers  
      //throws an error so that the coder can see why he effed up    
      throw "The second parameter must be a number. \n You passed: " + p_Number; 
      return false; 
   } 
 
   p_Number = new Number(p_Number); 
   switch(p_Interval.toLowerCase()){ 
      case "yyyy": {// year 
         this.setFullYear(this.getFullYear() + p_Number); 
         break; 
      } 
      case "q": {      // quarter 
         this.setMonth(this.getMonth() + (p_Number*3)); 
         break; 
      } 
      case "m": {      // month 
         this.setMonth(this.getMonth() + p_Number); 
         break; 
      } 
      case "y":      // day of year 
      case "d":      // day 
      case "w": {      // weekday 
         this.setDate(this.getDate() + p_Number); 
         break; 
      } 
      case "ww": {   // week of year 
         this.setDate(this.getDate() + (p_Number*7)); 
         break; 
      } 
      case "h": {      // hour 
         this.setHours(this.getHours() + p_Number); 
         break; 
      } 
      case "n": {      // minute 
         this.setMinutes(this.getMinutes() + p_Number); 
         break; 
      } 
      case "s": {      // second 
         this.setSeconds(this.getSeconds() + p_Number); 
         break; 
      } 
      case "ms": {      // second 
         this.setMilliseconds(this.getMilliseconds() + p_Number); 
         break; 
      } 
      default: { 
       
         //throws an error so that the coder can see why he effed up and 
         //a list of elegible letters. 
         throw   "The first parameter must be a string from this list: \n" + 
               "yyyy, q, m, y, d, w, ww, h, n, s, or ms.  You passed: " + p_Interval; 
         return false; 
      } 
   } 
   return this; 
} 
Date.prototype.dateAdd = dateAddExtention;