function IsDigit(cCheck)      
 {      
 return (('0'<=cCheck) && (cCheck<='9'));      
 }      
      
function IsAlpha(cCheck)      
 {      
 return ((('a'<=cCheck) && (cCheck<='z')) || (('A'<=cCheck) && (cCheck<='Z')))      
 }               
       
function IsaNull(cCheck)           
 {           
 return(cCheck != " ")          
 }