Odepax

// I use this to force the cursor to be a crosshair in diep.io as I think it's better for aiming than the arrow cursor.
// Just copy and paste this code snippet bellow in the browser console.
// The need for checking every 20s comes from the fact that the cursor is reset when hovering buttons (e.g. tank upgrade buttons).
// Cheking every 20s is quite smooth and does not decrease the game's performances.
// Alternatively, it's possible to opt for "move" instead of "crosshair" to get a fatter cross.
setInterval(function () {
	if (document.getElementById("canvas").style.cursor != "crosshair")
		document.getElementById("canvas").style.cursor = "crosshair"
}, 20000)

Odepax

// Note: the PDF must be image-based. Makes it not generic, but very usefull in some situations.
// Put this in the console:
// EXE: (function (pageId) { ... })("page3");
;(function(pageId = "page1") {
	const canvas = document.getElementById(pageId)
	const image  = new Image()

	image.src = canvas.toDataURL("image/png")

	document.body.innerHTML = null