Block default event in JS, block bubbling event __js

Block Default Events

1, in Javescript, return flase can prevent the default event, but must be added to the onmousedown incident, down to the end of the work, and then add back to Flase.

2, in the Custom function addevent, return flase will fail, please use the event object to block. Ev.preventdefault ()//block default event.

3, in the lower version of IE, these are not so, need to call in the OnMouseMove event obj.setcapture&&obj.setcapture (); and clearing Obj.releasecapture&&obj.releasecapture () in the OnMouseUp event;

Block event bubbling

Event bubbling:

1. When the child's event is triggered, the event of its parent is also triggered.

2, bubble and their display in the page regardless of the location, as long as in the HTML structure is a parent-child relationship, there is event bubbling.

3, prevent event bubbling must be added to the child. Blocked by the event object. Ev.cancelbubble=true;