I am setting the marginLeft attribut with javascript and it works fine in some browses but not safari or android.

I am trying to use the following javascript to set the left  margin for a contro.  It works fine in IE 7 and above and mozilla, but  not safari or android.  What do I have ot uses for safari and android.
 
I am presently using the following.
control.style.marginLeft = '13px';
...