Need custom action to work on click of tab for Embedded Component!!

Hi Experts ,

I have created a custom action to call a web service from c4c to crm/ecc.

Now my requirement is that when I click on the tab for Embedded component in the Opp B.O , the action should be triggered immediately and the web service call to determine the data should be done.

hoping for a quick answer,any reference or link to do so will be highly appreciable.

BR,

Daljeet