Firefox under the Easyui1.3.* pop-up window box can not be positioned to solve the middle problem

There is a problem in Firefox, pop-up window is not in the middle, but in IE and Google under the normal display, the solution is very simple to the body tag plus full-screen style can be resolved

Today in learning Easyui, there is a problem in Firefox, pop-up window is not in the middle, but in IE and Google under the normal, the following figure:

From the diagram can see that the problem is because the body of Firefox is not full screen, and IE under the full screen, you need to add a full screen of the body tag to solve the problem, this question is not known as the problem of Easyui or jquery.