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mirror of https://github.com/kkapsner/CanvasBlocker synced 2024-12-22 21:00:23 +01:00
CanvasBlocker/data/inject.js
2014-08-04 17:02:42 +02:00

59 lines
1.6 KiB
JavaScript

var getContext = unsafeWindow.HTMLCanvasElement.prototype.getContext;
var askFunctionName = Math.random().toString(16);
function checkPDF(blocking){
if (unsafeWindow.document.contentType.match(/\/pdf$/i)){
self.port.emit("isPDF", blocking);
return false;
}
return true;
}
function block(force){
if (force || !checkPDF("block")){
// consoe.log("block");
delete unsafeWindow.HTMLCanvasElement.prototype[askFunctionName];
unsafeWindow.HTMLCanvasElement.prototype.getContext = null;
}
}
function ask(force){
if (force || !checkPDF("ask")){
// console.log("ask");
Object.defineProperty(
unsafeWindow.HTMLCanvasElement.prototype,
askFunctionName,
{
value: getContext,
enumerabe: false
}
);
unsafeWindow.HTMLCanvasElement.prototype.getContext = new unsafeWindow.Function(function(){
var oldBorder = this.style.border;
this.style.border = "2px dashed red";
var confirmText =
this.parentNode?
"Do you want to allow the red bordered <canvas>?":
"Do you want to allow an invisibe <canvas>?";
var allow = confirm(confirmText);
this.style.border = oldBorder;
if (allow){
this.getContext = this["askFunctionName"];
return this["askFunctionName"].apply(this, arguments);
}
else {
return null;
}
}.toString().replace(/^function\s*\(\)\s*\{|\}\s*$/g, "").replace(/askFunctionName/g, askFunctionName));
}
}
function unblock(){
// console.log("unblock");
unsafeWindow.HTMLCanvasElement.prototype.getContext = getContext;
}
ask();
self.port.on("block", block);
self.port.on("ask", ask);
self.port.on("unblock", unblock);
self.port.on("detach", unblock);