WebAssembly's memory model piggybacks on the asm.js memory model, which uses a large typed ArrayBuffer to hold all of the raw bytes to be manipulated by the module. A JavaScript call to WebAssembly.Memory sets up the module's memory buffer in 64 KB pages.
A page is a block of linear data that is the smallest unit of data that can be allocated by an operating system, or, in the case of WebAssembly, a virtual machine. For more information on memory pages, see the Wikipedia Page: https://en.wikipedia.org/wiki/Page_%28computer_memory%29.
A WebAssembly module can only access data from within this ArrayBuffer. That prevents malicious attacks from WebAssembly that create a pointer to a memory address outside the browser's sandbox. Because of this design, WebAssembly's memory model is just as safe as JavaScript.
In the next section, we will be using...
