function checkEnter(e, form) { 
    //e is event object passed from function invocation
    var characterCode;  //literal character code will be stored in this variable
	
    if(e && e.which){ //if which property of event object is supported (NN4)
	e = e;
	characterCode = e.which; //character code is contained in NN4's which property
    }
    else{							
	e = event;						
	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)
	form.submit();
	return false;
    }
    else{
	return true;
    }
}