Authors CurseForge

local maxCrit = 0

local f = CreateFrame("Frame", "MyCritFrame", UIParent)
f:SetPoint("CENTER", UIParent, "CENTER", 0, 0)
f:SetWidth(150)
f:SetHeight(50)
f:Show()

f:SetBackdrop(GameTooltip:GetBackdrop())
f:SetBackdropColor(0, 0, 0, 0.8)
f:SetBackdropBorderColor(0.6, 0.6, 0.6, 1)

f:SetMovable(true)
f:EnableMouse(true)
f:RegisterForDrag("LeftButton")
f:SetScript("OnDragStart", f.StartMoving)
f:SetScript("OnDragStop", f.StopMovingOrSizing)
f:SetScript("OnHide", f.StopMovingOrSizing)

f.label = f:CreateFontString(nil, "ARTWORK")
f.label:SetPoint("LEFT", f, "LEFT", 10, 0)
f.label:SetFont("Fonts\\FRIZQT__.TTF", 30)
f.label:SetText("Crit:")
f.label:SetJustifyH("LEFT")

f.text = f:CreateFontString(nil, "ARTWORK")
f.text:SetPoint("LEFT", f.label, "RIGHT", 5, 0)
f.text:SetFont("Fonts\\FRIZQT__.TTF", 30)
f.text:SetJustifyH("RIGHT")

f.textMax = f:CreateFontString(nil, "ARTWORK")
f.textMax:SetPoint("LEFT", f.text, "RIGHT", 5, 0)
f.textMax:SetPoint("RIGHT", f, "RIGHT", 0, -10)
f.textMax:SetFont("Fonts\\FRIZQT__.TTF", 30)
f.textMax:SetJustifyH("RIGHT")

f:RegisterEvent("COMBAT_RATING_UPDATE")
f:RegisterEvent("UNIT_STATS")
f:SetScript("OnEvent", function(self, event, unit)
	if event == "UNIT_STATS" and unit ~= "player" then return end
	local crit = GetCritChance()
	self.text:SetFormattedText("%.2f", crit)
	if crit > maxCrit then
		maxCrit = crit
		self.textMax:SetFormattedText("%.2f", maxCrit)
	end
end)

Also, in the future, please use [ CODE ] tags around your code. Trying to read more than 2-3 lines without proper indentation sucks.

If you want it to have a "dialog box" style border:

myframe:SetBackdrop({
	bgFile = [[Interface\DialogFrame\UI-DialogBox-Background]],
	edgeFile = [[Interface\DialogFrame\UI-DialogBox-Border]],
	tile = true,
	tileSize = 32,
	edgeSize = 32,
	insets = { left = 11, right = 12, top = 12, bottom = 11 },
})

Don't forget to SetPoint the frame, or it won't be visible.

myframe:SetPoint("CENTER", UIParent, "CENTER", 0, 0)