Eliminating warning in HTML

user1221330

I am creating 3 jsp pages. There are 4 boxes with different id in each pages (i.e. box1, box2, box3, box 4 in page 1; box 5, box6, box7, box8 in page 2; box9, box10, box11, box12 in page 3). Below is the sample code in page 1:

<div class="dragableBox" id="box1">CAT</div>
<div class="dragableBox" id="box2">DOG</div>
<div class="dragableBox" id="box3">HORSE</div>
<div class="dragableBox" id="box4">TIGER</div>

In each page there is also a script. In the script I deliberately use all those ids above as parameters of a function. Below is the sample code in page 1:

dragDropObj.addSource('box1',true);
dragDropObj.addSource('box2',true);
dragDropObj.addSource('box3',true); 
dragDropObj.addSource('box4',true); 
dragDropObj.addSource('box5',true); 
dragDropObj.addSource('box6',true); 
dragDropObj.addSource('box7',true); 
dragDropObj.addSource('box8',true); 
dragDropObj.addSource('box9',true); 
dragDropObj.addSource('box10',true);    
dragDropObj.addSource('box11',true);    
dragDropObj.addSource('box12',true);    

I must do this because as far as I know this is the only way for my program to work. The problem I encounter is that each time the program started, a warning appears:
“The source element with id box5 does not exist”

Although the program still works fine with this warning, I still want to eliminate the warning.

My question here is:
How can I stop such warning from appearing?
Is there a kind of error catching method in HTML?