DLL extension to manipulate web browser form

I need to develop a DLL that will be used as an #include within a Metatrader4 script (uses C language) and used locally on my computer. The DLL will have functions to send information from the Metatrader4 application to a web browser (either Explorer, Google Chrome or Firefox). Specifically, the DLL will do the following: 1. Accept 6 variables of type int and double as parameters 2. Enter this data on a webpage form 3. Submit the form The method you choose to do this is up to you but please provide the method(s) you will tentatively use to achieve this so that I can determine what would be the better-performing method from the proposals. The main concern is speed. This needs to be very fast. I have attached the webpage where the information will be input into. This webpage is online on a third-party website. The actual forms are pop-up DIVs that you can see when you individually click each currency's price quote. The DLL parameters will be all the information needed to select the correct form from the webpage, and fill the aprropriate field values: a) the currency's symbol; 2) whether it's a buy or sell order; 3)the order type (market or price-based); 4) rate field; 5) stop field; 6) limit field. Note: If you think this would be better achieved by using something other than a C DLL, such as DDE, custom browser plug-in, .NET, JAVA, ActiveX control, etc... then please make a note of that on your proposal.