Question - How to write a script for "Select" lists using javascript? 
          
        
        Answer - 
        1. To remove an item from a list set it to null 
mySelectObject.options[3] = null; 
2. To truncate a list set its length to the maximum size you desire 
mySelectObject.length = 2; 
3. To delete all options in a select object set the length to 0. 
mySelectObject.leng