function FormCheckEnterKeyed(e){ 
var characterCode;

if(e && e.which){ //if which property of event object is supported (NN4)
characterCode = e.which; //character code is contained in NN4's which property
}
else{
characterCode = e.keyCode; //character code is contained in IE's keyCode property
}

if(characterCode == 13){ //if generated character code is equal to ascii 13 (if enter key)
return true; 
}
else{
return false; 
}
}