I hope you are correct. For my startup, I've assumed you are correct. Since my startup is my first Web site, I'm no expert in the issues in the OP here. So,

I hope you are correct. For my startup, I've assumed you are correct. Since my startup is my first Web site, I'm no expert in the issues in the OP here. So, HELP! Guys here who know more than I do about Web apps on different Web browsers on different client devices, which is nearly everyone on HN, help me out here -- am I on or off track? Where am I going wrong? So, what I've built is just a Web site (Web app). For the code to run in production, it's about 20,000 programming language statements in about 80,000 lines of typing. It's nearly all in Visual Basic .NET 4.0 with ASP.NET and ADO.NET. For the user's browser, the user interface (UI), and user experience (UX) the site is all old and simple, dirt simple. My guess is that the Web pages should look fine on any device with a Web browser up to date as of 10+ years ago. So, the site is just simple, standard, old HTML and a little really simple CSS. The CSS is all in the same file as the HTML. Microsoft wrote a little JavaScript for me, but I never wrote a single line of it. There is no use of Ajax. So far there is no use of cookies. So, for one Web page, what goes to a user is just one HTML file with CSS, a small JavaScript file, likely standard from Microsoft, and a file for each of the images. The fonts are large and standard. The colors are simple with high contrast. For images, there are ads in the two standard sizes, banner ads 720 pixels wide and 90 pixels high and other ads 300 pixels wide and 250 pixels high. Otherwise the images are just a few, simple, small PNG files for logos. The only HTML controls are single line text boxes, buttons, and text with links. There are no roll overs, pull downs, pop ups, or icons. There is no auto-complete. The natural language on the site is all English, but it is all very simple, and the user interface is so simple that a person with no knowledge of English should be able to learn to use the site in less than 15 minutes. The page layout is all done with just tables with all widths fixed. E.g., each Web page is exactly 800 pixels wide. Since there are both horizontal and vertical scroll bars, the Web pages should be usable in a window as narrow as 300 pixels wide and 200 pixels high. Each Web page sends for about 400,000 bits (except for the ads from ad servers). The reason for people to use the site is for the information it provides. The site is quite interactive, and there is an iterative, game aspect as in games where wander through tunnels with clues and looking for coveted prizes. Maybe for some users the site will have an addictive quality. From what details I've given, is it likely that the Web pages are simple enough to work on nearly all current Web browsers on whatever client side devices? Where am I going wrong? Thanks.