Navigation bar style, the navigation bar is blocked by other elements, how to break?

The navigation bar for jquery scripts downloaded from the Web.
There is a level two menu, after the following table, the following picture of what the navigation bar of the two-level menu blocked, how can I set the level two menu to display on the top floor?

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The navigation bar for jquery scripts downloaded from the Web.
There is a level two menu, after the following table, the following picture of what the navigation bar of the two-level menu blocked, how can I set the level two menu to display on the top floor?

Comparison of hierarchical relationships

1. For sibling elements, the elements that follow the document flow in the default (or position:static) case will overwrite the previous.

2. For sibling elements, position is not static and Z-index exists z-index the large element overrides the Z-index small element, that is, the greater the Z-index the higher the priority.

3. Ie6/7 under position is not static, and Z-index does not exist when Z-index is 0, in addition to the browser Z-index for auto.

4. Z-index elements that are auto are not involved in the comparison of hierarchical relationships, and are represented by elements that traverse up to this and z-index not auto.

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