Is there any function to Form like Head->AddString so that i can inject html from plugin?
Try the plugin Eventi. It will show you "where" you can add code. Then look at some plugins on how it could be done: http://vanillaforums.org/addon/addtexttobox-plugin
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Try the plugin Eventi. It will show you "where" you can add code. Then look at some plugins on how it could be done: http://vanillaforums.org/addon/addtexttobox-plugin