Applicant has discovered an in situ method of preparing quaternary ammonium methocarbonate salts and quaternary ammonium alkylcarbonate salts in high yield from tertiary amines, methanol, and at least one of a cyclic carbonate, an aliphatic polyester, or an ester, and their subsequent conversion to quaternary ammonium bicarbonates, quaternary ammonium carbonates or both in a one-pot reaction. The method uses a plurality of light sources of different color temperatures as a backlight of the LCD and controls relative quantities of light from the light sources to adjust the color of the monochromatic image displayed on the LCD or each of the LCDs. After confirming the company profile of the Internet portal site, a user can speak by telephone with a person in charge of a company without a waiting time for call connection, and the user can rapidly acquire necessary information by means of query and response.