function validateHalfSizeChar(form) {
        var isValid = true;
        var focusField = null;
        var i = 0;
        var fields = new Array();

        oHalfSizeChar = eval('new ' + form.name + '_halfSizeChar()');

        for (x in oHalfSizeChar) {
            var field = form[oHalfSizeChar[x][0]];

            if (field.type == 'hidden' ||
                field.type == 'text' ||
                field.type == 'password' ||
                field.type == 'textarea') {

				if (!field.value.match(/^[a-zA-Z0-9_\-]+$/)) {
                    if (i == 0) {
                        focusField = field;
                    }
                    fields[i++] = oHalfSizeChar[x][1];
                    isValid = false;
                }
            }
        }
        if (fields.length > 0) {
           focusField.focus();
           alert(fields.join('\n'));
        }
        return isValid;
    }