Interacting with svg

I am using mapserver to create an svg document inside an html page. The svg is being created autmatically by the mapserver so I cannot change it at the time of its creation.
Mapserver runs on a server and with php commands I get the svg file on an HTML page.
The question is how I can interact with this svg afterwards. For example how I can use onclick methods, zoom in zoom out etc. 
As far as I have seen in order to use this methods you have to import them inside the svg code, but unfortunately this is not my case.
I have a feeling that I must use HTML DOM but I dont know how to do this.

Can anyone help me?

Thank you in advance.