Adds a red corner pointer to the given pixel coordinates. Useful for quickly determining where exactly the given coordinates are on the screen.

addPointer.js

function addPointer(x, y) {
	$('body').append('<div style="position:absolute; left: ' +
    x +
    'px; top: ' +
    y +
    'px; border-left: 3px solid red; border-top: 3px solid red; box-sizing: border-box; width: 10px; height: 10px; z-index:1000000000;"></div>');
}