function validate_email(emString)
{
 var emaData=
 [ 
  /\,/,     false,  "Comma (,) found",
  /\s/,     false,  "Spaces not allowed",
  /@/,      true,   "No @ sign",
  /@.*@/,   false,  "Too many @s",                     
  /^@/,     false,  "Nothing preceding @",
  /\.@/,    false,  "@ preceded by '.'",
  /@\./,    false,  "@ followed by '.'",                      
  /@.+\./,  true,   "No '.' anywhere after @",
  /\.\./,   false,  "=>..",       
  /^\./,    false,  "Cannot start with '.'",
  /\.$/,    false,  "Cannot end with '.'",
  /.+\.([a-z]{2,}|\d{1,3})$/i, true, "Must end with 2 or more letters or 1-3 digits"
 ];
 var ok=true, dl=emaData.length;

 emString=emString.replace(/^\s+|\s+$/g,'');  
  
 for(var i=0; i<dl && ( emaData[i].test( emString ) ^ !emaData[i+1] ); i+=3) 
 ; 
  
 if(i!=dl)
 {
  ok=false;
  alert("Error in format of e-mail address:\n\n" + emString + "\n\n" + emaData[i+2]);
 }
  
 return ok;
}