/*控制主导航鼠标样式*/

    function NavBg(nav)
    {
      document.getElementById("aboutus").style.backgroundColor="#43949f";
      document.getElementById("aboutus").style.backgroundImage="url(images/arrowblue.gif)";
    }
    function ChangeNavBg(id,nav)
    { 
      
      if(document.getElementById(id).id!=nav)
      {
        document.getElementById(id).style.backgroundColor="#43949f";
        document.getElementById(id).style.backgroundImage="url(images/arrowblue.gif)";
      }
      else
      {
        document.getElementById(id).style.backgroundColor="#43949f";
        document.getElementById(id).style.backgroundImage="url(images/arrowblue.gif)";
      }
    }
    function UnChangeNavBg(id,nav)
    {
      if(document.getElementById(id).id!=nav)
      {
        document.getElementById(id).style.backgroundColor="#9eb701";
        document.getElementById(id).style.backgroundImage="url(images/arrow.gif)";
      }
      else
      {
        document.getElementById(id).style.backgroundColor="#43949f";
        document.getElementById(id).style.backgroundImage="url(images/arrowblue.gif)";
      }
    }