4 ms·

This is awesome -- you never know when a solution like this might come in handy. Wayyyyy back in the day (NS4, IE4 day) I used the width / height of an image t

by arscan 14y ago

This is awesome -- you never know when a solution like this might come in handy. Wayyyyy back in the day (NS4, IE4 day) I used the width / height of an image the browser polled every few seconds as a transport mechanism... the only other option (refreshing a hidden frame) caused an irritating "page refresh" clicking noise. This was before XMLHttpRequest obviously and was enough bandwidth for our needs. It worked so well that I believe its still being used in production systems. I haven't looked at the javascript generated in this animated gif solution, but I assume that it does some stuff that wouldn't work in the pre-IE6 browsers. It would be extremely amazing if it did though.

old_sound 14y ago
This doesn't use any javascript
arscan 14y ago
Ah, I just realized that this simply prints text out in a gif... it doesn't encode text in the gif and then decode it in the browser into text that javascript could manipulate. Too bad. I wonder if that's possible...
- streptomycin 14y ago
  It is possible, as you can now get the raw pixel data of an image by copying it to a canvas and using getImageData. <img src="test.gif" id="img"> <script type=text/javascript> var img = document.getElementById("img"); var canvas = document.createElement("canvas"); canvas.width = img.width; canvas.height = img.height; var ctx = canvas.getContext("2d"); ctx.drawImage(img, 0, 0); var imageData = ctx.getImageData(0, 0, canvas.width, canvas.height); </script> Then you can do whatever you want with the pixel data.
  - mmastrac 14y ago
    Unfortunately not on IE6, and this would require both canvas support and CORS. I think most browsers that support that also support true web sockets.
  - arscan 14y ago
    This would be a great step in some kind of rube goldberg inspired website.
- xxbondsxx 14y ago
  Encoding data into images is certainly possible, albeit sometimes a PITA.
gfodor 14y ago
Awesome. I did this trick too, many years ago. I stole it from Liveperson I think.
kragen 14y ago
When we were doing Comet in Netscape 4 and IE4 at KnowNow (in 2000, although Rohit, Adam, and Peyman got the technique working in 1999), we used an endless HTML frame, which simply never stopped loading. We'd spit out a <script> tag whenever there was a new message to deliver. There was an annoying clicking noise in IE, but only when the frame did finish loading because you'd lost your network connection or restarted the server. This eventually got open-sourced as "mod_pubsub".
- riobard 14y ago
  There you go, Facebook's BigPipe!

by arscan 14y ago

old_sound 14y ago

This doesn't use any javascript

arscan 14y ago

Ah, I just realized that this simply prints text out in a gif... it doesn't encode text in the gif and then decode it in the browser into text that javascript could manipulate. Too bad. I wonder if that's possible...

streptomycin 14y ago
It is possible, as you can now get the raw pixel data of an image by copying it to a canvas and using getImageData. <img src="test.gif" id="img"> <script type=text/javascript> var img = document.getElementById("img"); var canvas = document.createElement("canvas"); canvas.width = img.width; canvas.height = img.height; var ctx = canvas.getContext("2d"); ctx.drawImage(img, 0, 0); var imageData = ctx.getImageData(0, 0, canvas.width, canvas.height); </script> Then you can do whatever you want with the pixel data.
- mmastrac 14y ago
  Unfortunately not on IE6, and this would require both canvas support and CORS. I think most browsers that support that also support true web sockets.
- arscan 14y ago
  This would be a great step in some kind of rube goldberg inspired website.
xxbondsxx 14y ago
Encoding data into images is certainly possible, albeit sometimes a PITA.

gfodor 14y ago

Awesome. I did this trick too, many years ago. I stole it from Liveperson I think.

kragen 14y ago

When we were doing Comet in Netscape 4 and IE4 at KnowNow (in 2000, although Rohit, Adam, and Peyman got the technique working in 1999), we used an endless HTML frame, which simply never stopped loading. We'd spit out a <script> tag whenever there was a new message to deliver. There was an annoying clicking noise in IE, but only when the frame did finish loading because you'd lost your network connection or restarted the server. This eventually got open-sourced as "mod_pubsub".

riobard 14y ago
There you go, Facebook's BigPipe!