how to connect two entities in ERD by using click event

[maqthadar khan]

hi...iam new to this joint js...i want to know how to connect two
entities by clicking on them..for ex.there are two rectangles
dynamically created and when we click these two rectangles there
should form a path between them dynamically through event
functions.can any one tell me ..my code is
rec.wrapper.click(function()
{
firstobject=this.node;
the above statement is not working...