[nosir33]

Sample code to execute some Javascript code inside PyPy.js. I couldn't find any examples.

    import js
    js.eval("console.log(\"hi!\")")

[fragmede]

It's a bit messy, but:

    js.eval('var div = document.createElement("div"); div.style.width = "100px"; div.style.height = "100px"; div.style.background = "red"; div.style.color = "white"; div.innerHTML = "Hello"; document.body.appendChild(div);');

manages to append a div.

--

Directly modifying document.body.innerHTML in any way seems to hang it. Both:

    js.eval('document.body.innerHTML += "<div></div>";');
    js.globals.document.body.innerHTML += "<div></div>"

Cause it to hang, though the javascript console shows it was added (or using an img tag instead).

(ChromeOS v43 beta)

[batbomb]

It's more fun doing this, since jQuery is already on the page:

    import js
    jq = js.eval("$")
    first_line = jq(jq(".container p")[0])
    first_line.text("jQuery was here")

[Retr0spectrum]

Just playing around:

    import js
    c = js.globals.document.createElement("canvas")
    js.globals.document.body.appendChild(c)
    ctx = c.getContext("2d")
    ctx.fillRect(10, 10, 10, 10)

Edit: Here is a simple animation:

    import js
    import math
    import time
    c = js.globals.document.createElement("canvas")
    js.globals.document.body.appendChild(c)
    ctx = c.getContext("2d")
    
    def render():
      ctx.clearRect(0, 0, c.width, c.height)
      t = time.time()
      ctx.fillRect(20+math.sin(t*10)*10, 20+math.cos(t*10)*10, 10, 10)
    
    js.globals.window.setInterval(render, 20)

Here's a version you can paste in properly: http://pastebin.com/raw.php?i=67GadSUV

[fragmede]

Sadly, if I paste that in, I get:

    >>> import js 
    ... c = js.globals.document.createElement("canvas") 
    ... 
    debug: OperationError:
    debug:  operror-type: SyntaxError
    debug:  operror-value: ('EOL while scanning string literal', ('c callback', 1, 12, "r = c.push('import js\n", 0))
    debug: OperationError:
    debug:  operror-type: KeyError
    debug:  operror-value: 'r'

And then the input window hangs. Strangely enough, if I type it in instead, it's okay.

(ChromeOS v43 beta-channel)

[Retr0spectrum]

I think the only way around it is to paste each line separately. It seems to be caused by newline characters in the wrong place

[fragmede]

'that' refers to

    import js
    c = js.globals.document.createElement("canvas")

and not the pastebin. The pastebin works for me, but only the first time. Subsequent runs result in:

    <RuntimeError object at 0x15d648>
    RPython traceback:
      ...
    Fatal RPython error:

[dag11]

Or this:

    import js
    js.globals.console.log('hi!')

[catlover99]

I'm loving this, my head is reeling with the glint of possibilities

    import js
    js.globals.console.log('hi!'*5)

[e12e]

Seems to be some issues with the interop still, eg:

  import js
  >>> "globals" in dir(js)
  True
  >>> "console" in dir(js.globals)
  False
  >>> js
  <module 'js' (built-in)>
  >>> js.globals.console
  <js.Object handle=14>

So apparently introspection doesn't quite work with the wrapped js. Also, if you try: "[ i for i in js.globals]" (or equivalently iterate/loop over the globals-object) - the whole repl/tab hangs.

Not really an issue for running business logic in the browser, but if this was a full python repl-interface (with ipython support!) to the whole browser DOM -- that'd be a fantastic tool.

[bzbarsky]

The introspection bit is because js.globals is implemented with a fancy __getattr__ but doesn't have a __dir__. In general, dir() is not reliable in the face of custom __getattr__ implementations unless the implementor goes out of the way to make it work.

[e12e]

Oh, right. I didn't consider that:

  Welcome to PyPy.js!
  >>> import js
  >>> "console" in js.globals
  True
  >>> "console" in dir(js.globals)
  False

[stuaxo]

It would be good if they could support a common api with brython, which has "import web" and some other bits...

I guess these things will take a while to shake out, but I'd imagine a python-in-browser-api PEP at some point.