Web Assembly is a new low-level language for browsers that is intended to be a compilation target from other languages like C/C++. It allows for typed variables, multi-threading, and fast loading/parsing for running heavy applications in browsers, like games, video/image processing, and virtual reality. Web Assembly aims to be as fast as native code and may impact the future role of JavaScript for advanced applications in browsers. It is still under development by the major browser vendors.

1. What is it & How will it affect JavaScript
By Ziv Birer, Technical lead with HPE Software

2. Netscape
(1995)
Server
(2009)
Mobile
(2010)
Web
Assembly
(2015)

3. • Games
• Video processing
• Image processing
• Virtual reality

5. Subset of JS + hints
• Static typed variables
• Only “low level” operation
“asm.js” mode
• Precompile all code
• Performance optimizations
• No garbage collection

6. Vertical bar 0
integer
asm.js code
function _main() {
"use asm";
var $0 = 0, $vararg_buffer = 0, label = 0;
var sp = 0; sp = STACKTOP;
STACKTOP = STACKTOP + 16|0;
if ((STACKTOP|0) >= (STACK_MAX|0))
abort();
$vararg_buffer = sp; $0 = 0;
(_printf(672,$vararg_buffer)|0);
STACKTOP = sp;
return 0;
}
Simple code
Valid JS code

9. 9
• A new browser language
• Compilation target from other language
• Typed variables
• Multi threaded
• Garbage collection
• Load fast (quick parsing)

10. asm.js
function () {
"use asm";
function add(x, y) {
x = x | 0;
y = y | 0;
return x + y | 0;
}
return { add: add };
}
(module
(export $add “add” $add)
(func $add
(param $x i32)
(param $y i32)
(result i32)
(i32.add
(get_local $x)
(get_local $y)
)
)
)
web assembly

12. Web Applications• Games
• CAD
• Video editing
• Image editing
• Scientific visualization
• Virtual reality
• Augment reality

13. 48
photo: panoramio.com
Summary
New “low level” language of browsers
It is a “target” language (from C/C++)
Fast almost as native languages
For running “heavy” applications on the browser
Still under development
May affect future of JavaScript@bmihaylov | Voxxed Days Thessaloniki 2016

14. Thank you !