输入框提示tip

<script type="text/javascript">
    var pltsoffsetX = 10; // 弹出窗口位于鼠标左侧或者右侧的距离；3-12 合适
 var pltsoffsetY = 12; // 弹出窗口位于鼠标下方的距离；3-12 合适
 var pltsTitle="";
 document.write('<div id=pltsTipLayer align=center style="FILTER:alpha(opacity=90); vertical-align: middle; display: none;width: 200;height: 20;position: absolute; background-color: white;border: 1px solid #000000">请输入正确的日期格式，如2008-09</div>');
    function displayTip()
    {
     var pltsTip = document.getElementById('pltsTipLayer');
     pltsTip.style.display="block";
     var MouseX=event.x;
   var MouseY=event.y;
   var popTopAdjust=0;
   var popLeftAdjust=0;
   var popHeight=pltsTipLayer.clientHeight;
  var popWidth=pltsTipLayer.clientWidth;
      if(MouseX+pltsoffsetX+popWidth>document.body.clientWidth)
  {
   popLeftAdjust=-popWidth-pltsoffsetX*2;
  }
  else
  {
    popLeftAdjust=0;
  }
  pltsTipLayer.style.left=MouseX+pltsoffsetX+document.body.scrollLeft+popLeftAdjust;
  pltsTipLayer.style.top=MouseY+pltsoffsetY+document.body.scrollTop+popTopAdjust;
  
    }
   
    function hideTip()
    {
     var pltsTip = document.getElementById('pltsTipLayer');
     pltsTip.style.display="none";
    }
 </script>

 

onfocus="displayTip();"

onblur="hideTip();"