The cells.findXy() method finds Scheduler cells by their grid coordinates (indexes, not pixels).
DayPilot.Scheduler.cells.findXy(x, y)
DayPilot.Scheduler.cells.findXy(coordinates)x (number) - horizontal cell index, starting at 0 in the upper-left corner
y (number) - vertical cell index, starting at 0 in the upper-left corner
coordinates (array) - an array of coordinate objects, for example [{x: 0, y: 0}, {x: 0, y: 1}]
Returns an array of matching cells. The returned collection exposes helper methods that modify all cells in the array:
addClass(className) - adds a CSS class to all matched cells
removeClass(className) - removes a CSS class from all matched cells
html(string) - sets the HTML content of all matched cells
Writes test HTML to the cell in the upper-left corner:
dp.cells.findXy(0, 0).html("test");