I bind my canvas "Drawing_Plate" with several events:

                $("#Drawing_Plate").unbind("touchstart");

$("#Drawing_Plate").unbind("touchmove");

$("#Drawing_Plate").unbind("touchend");

Line 13: $("#Drawing_Plate").bind("touchstart",put_the_bgrd_music); //put_the_bgrd_music is a function().

Line 14: $("#Drawing_Plate").unbind("touchstart");

As I expect,  $("#Drawing_Plate").unbind("touchstart");  will execute after Line 13: As the user touch on the canvas, doing something and then the  $("#Drawing_Plate") stop receiving the event.  

However,  it didn't...

1.  I would like to know why?  
We usually wait for the complete execution of a function or instrument 
in C++/ Java/ C/ C#...
And then the codes after it can execute. But it didn't. 

2. Is it the property of Javascript or just for the method .bind()?

3.  I have saw other people will use "successful callback" to overcome this issue? If the Line 13 complete, we let line 14 to execute. But it's bothering. Is this the only approach we can take?

4.  Conclusion?  What's the problem at all?  It's not the only case that I encounter this kind of problem...

                                                Thanks, I really need specific explanation and help. You can provide some external links and I will study it.
I think I lack of some important concept in both javascript and jQuery. 

ps: Is that because multiple thread?