Allow a Scratch 2.x project to be embedded in BBcode

scratchproj3.js

// Usage: [scratch]projectID[/scratch]

var posts = document.getElementsByClassName("postmsg");
var pattern = /\[scratch\]([0-9]+)\[\/scratch\]/gi;

for (var i = 0; i < posts.length; i++) {
  var post = posts[i];
  post.innerHTML = post.innerHTML.replace(pattern, "<iframe allowtransparency=\"true\" width=\"485\" height=\"402\" src=\"http://scratch.mit.edu/projects/embed/$1/\" frameborder=\"0\" allowfullscreen></iframe>");
}