HTML and CSS Reference
In-Depth Information
Figure20.Demonstrating how to view the application interface for the video element in Chrome
(Canary Build)
For all the browsers, you may need to specifically enable script debugging the first time you
access the debugger. Check with the browser documentation to find out the details.
All browser debuggers support the same technique to set a break point: you click to the left
of the line number of the code line where you want program execution to pause. When you
reload the page or restart the script (whatever you need to do to trigger the break point in the
debugger), the code execution halts at this break point.
Another universal: explore the local variables in a box to the right of the debugger. In this
case, the local variables we're interested in are
audioobj
and
videoobj.
The reason for the
third line of code in the script block is so that we have a break point we can reach afterthese
objects have been created.
Firebug, Dragonfly, and the Chrome and Safari debuggers display a list of local variables in a
single pane with other variables, but should be immediately apparent. With Dragonfly, they're
in a panel labeled
inspection
; for Chrome and Safari, they're in a panel labeled with
Scope
Variables
; in Firebug, clicking the
Watch
tab brings up the local (and global) variables, with
the local variables, first. With IE, you'll need to click the
Locals
tab in the right side of the
debugger.
