WYSIWYG stands for "What You See Is What You Get", so if you are using a WYSIWYG editor to design and create your web page, you have a pretty good idea of how the page will look in a web browser. Think of Microsoft Word when you change a font, you see the font change immediately in the MS Word document. The same is true in a WYSIWYG Editor, in that you see changes immediately within the editor itself, as opposed to having to save the page and then separately load and view it in a web browser.