Layout in AMP

The reason we must provide width, height, and layout attributes for images is to do with how AMP calculates the layout of the page. AMP uses a static layout system so that it can render pages more quickly. If the AMP runtime has this information upfront, in the markup, then it can always know how much space any element will take up. This means it can calculate the layout of the page efficiently even before external resources are loaded, and without having to reflow the page as they are loaded. We'll look at the AMP layout attribute in more detail in the next chapter.

We've just had our first encounter with HTML tag restrictions in AMP. Now's a good time to take a look at what tags are or aren't permitted.