I visit sites where some features like pop-up menus and tooltips are invoked by placing the mouse cursor over an item. I would like to use all the features while using my Android tablet. So, I'm looking for a way to simulate the mouse-over event in Android browser, especially in Android 4.1.2
The long-click is basically the same as a right-click which brings up context menus.
Things for mouse-over such as viewing titles, and link urls can be accomplished with bookmarklets. I have examples bookmarklets to view all titles, and all href links, see "href:", "href-x:" and "parentips" on for instance my dolphin gestures page. You can invoke example by clicking on one of those boxed bookmarklets links.
To learn more about bookmarklets, if you are not familiar with them, I would suggest starting at http://www.squarefree.com/bookmarklets.
Long-press the item (to open its context-menu), then hit the "back" key (to leave the menu). Works on most devices. Explained e.g. here, scroll down to "Smartphones".