// Check if a string is a digit (i.e. no minus sign or decimal point)

function isDigit(str)
{
	for (var i = 0; i < str.length; i++)
	{
		var c = str.substring(i,i+1);
		
		if (c < "0" || c > "9") return false;
	}
	return true;
}

//************************************************************************

// Check if a string is a valid email format (NOT comprehensive)

function isEmail(str)
{
	var chk1 = str.indexOf("@");
	var chk2 = str.indexOf(".");
	var chk3 = str.charAt(chk1-1);
	var chk4 = str.charAt(chk2-1);
	var chk5 = str.charAt(chk2+1);

	if (chk1 == -1 || chk2 == -1 || (chk1 > chk2) || chk3 == "" || chk4 == "@" || chk5 == "") return false;

	return true;
}


function isimg(str)
{
	var chk1 = str.indexOf("jpg");
	var chk2 = str.indexOf("gif");


	if (chk1 == -1){
	  if (chk2 == -1) return false;
	
	}
      return true;
}




//************************************************************************

// General purpose error message

function submitError(obj,msg,def)
{
	alert("SUBMIT ERROR\n" + msg);		// display error alert using msg
	obj.focus();						// send focus to obj where error occurred
	obj.value = def;					// set default value for input field after error
}

//************************************************************************