function trim(s) {
      s = s.replace(/^\s+/,"");
      return s.replace(/\s+$/,"");
}

function require(form, spec) {
    for (i = 0; i < spec.length; i += 2) {
        name = spec[i];
	text = spec[i+1];

	field = eval("form." + name);

	if (field.type) {
	    val = trim(field.value);

	    field.value = val;

	    if ("" == val) {
		alert(text);
		return false;
	    }
	} else {
	    checked = false;
	    for (j = 0; j < field.length; j++) {
		cbox = field[j];
		if (cbox.checked) {
		    checked = true;
		    break;
		}
	    }
	    if (!checked) {
		alert(text);
		return false;
	    }
	}
    }
    return true;
}