Zoom in: click left mouse button inside the plot for start time, drag until end time, and release
Zoom out: double-click on the plot
Smooth: specifiy in bottom-left corner box and hit enter (click outside plot in Opera,IE)
Pan: while zoomed in, hold down Shift key and drag to pan
S/W used & Browser compatibitliy: Library: DYGraph visualization.
All modern browsers like FF, Safari, Opera etc. supporting HTML5 'canvas' tag. For IE, 'excanvas' is used but it appears slow and IE is not recommended here.