How to get node id by mouse click

I want to implement: Return the node id when a mouse click is made near a node in the model.

I has been realized by use:

*createmarkpanel nodes 1 set id_list [hm_getmark nodes 1] 

But calling *createmarkpanel will bring up the panel for selecting nodes, and I have to click on process button, which is a tedious step.

Any help is appreciated!