//限定宽度显示图片
function drawImageFitWidth(obj,FitWidth)
{
  image=obj 
  if(image.width>0 && image.height>0)
  {
      if(image.width>= FitWidth)
      {
        image.width=FitWidth;
        image.height=(image.height*FitWidth)/image.width;
      }    
  }  
}
//限定高度显示图片
function drawImageFitHeight(obj,FitHeight)
{
  image=obj 
  if(image.width>0 && image.height>0)
  {
      if(image.height>= FitHeight)
      {
        image.height=FitHeight;
        image.width=(image.width*FitHeight)/image.height;
      }    
  }  
}
//限定高度和宽度显示图片
function drawImageFitHW(obj,FitWidth,FitHeight)
{
  image=obj 
  if(image != null)
  {
      if(image.width>0 && image.height>0)
      {
          if(image.width>= FitWidth && image.height>= FitHeight)
          {
            if(image.width/image.height>= FitWidth/FitHeight)
            {
                image.width=FitWidth;
                image.height=(image.height*FitWidth)/image.width;
            }
            else
            {
                image.height=FitHeight;
                image.width=(image.width*FitHeight)/image.height;
            }       
          }    
          else if(image.width>= FitWidth && image.height < FitHeight)
          {
                image.width=FitWidth;
                image.height=(image.height*FitWidth)/image.width;
          }    
          else if(image.width < FitWidth && image.height >= FitHeight)
          {
               image.height=FitHeight;
               image.width=(image.width*FitHeight)/image.height;
          }
      }  
      else
      {   
            image.width=FitWidth;
             image.height=FitHeight;
      }
  }  
}