How to : draw Tree & Graph structures ?

How to : draw Tree & Graph structures ?

Hi all.

I am trying to draw on html page a structure called Graph : http://en.wikipedia.org/wiki/Graph_%28data_structure%29 .

Another possible structure i have to draw is Tree : http://en.wikipedia.org/wiki/Tree_%28data_structure%29

Is there around any plugin or hints on how it can be done ?

I found interesting plugins for charts ... but they don't help enough for these goals.

Best would be if nodes could be clicked to collapse sub-trees ( i know it's not a problem for jquery, once some plugin can manage tree and graph )

Any suggestion very appreciated.

Many thanks in advance.

Kind Regards,
Maurizio
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