You can easily zoom in a graph using set_cursor() function and set the property “zoom” to true. It requires non-renderer plugin “cursor“.
Click an area on the graph, then drag the mouse to zoom in. Double click anywhere to reset zoom in level. Zooming also works multiple axes.
Complete cursor plugin reference can be found at http://www.jqplot.com/docs/files/plugins/jqplot-cursor-js.html