DButton.OnMousePressed

 
Frame = vgui.Create( "DFrame" )
	Frame:SetSize( 150, 75 )
	Frame:Center()
	Frame:SetTitle( "Title" )
	Frame:MakePopup()
 
button = vgui.Create( "DButton", Frame )
	button:SetSize( 100, 25 )
	button:SetPos( 25, 25 )
	button:SetText( "Press Me" )
	button.OnMousePressed = function()
		button:SetText( "Pressed" )
	end
 
	button.OnMouseReleased = function()
		button:SetText( "Not Pressed" )
	end
 

 
Frame = vgui.Create("DFrame")  -- make a frame
	Frame:SetSize(150, 75)
	Frame:Center() -- places the frame in the center of your screen
	Frame:SetTitle( "Frame Title" ) 
	Frame:MakePopup() -- activates the cursor so you can click stuff
 
button = vgui.Create("DButton", Frame) -- create a DButton, parent it to Frame
	button.Colour = Color(100, 100, 100, 255) -- Assign The Button This Variable, So We Can Change The Colour Without Having A Complex Paint Function.
	button:SetText( "Press Me" ) -- initial text on the button
	button:SetPos(5, 25) -- position relative to the frames top left corner
	button:SetSize( 100, 25 ) -- set the buttons dimentions
 
	button.Paint = function() 
		surface.SetDrawColor(button.Colour) -- anything we draw will be the colour saved in button.Colour
		surface.DrawRect(0, 0, button:GetWide(), button:GetTall()) -- create a rectangle that covers the button
	end
 
	button.OnMousePressed = function() 
		button.Colour = Color(0, 200, 0, 255) -- give the variable this green colour, because the Paint function is updated every frame, the button will change to green
	end
 
	button.OnMouseReleased = function() 
		button.Colour = Color(200, 0, 0, 255) -- and when released, the button turns red
	end