//ΛΔΙαΞεΘλΊ―Κύ
   function  cheng(num,n)  
   {  
      if(String(num).match(/^((\d+\.\d+)|\d*)$/)==null)
	  {
		 alert("Input need a number !")
	     return "0.00"
	  }
      var  dd=1;  
      var  tempnum;  
      for(i=0;i<n;i++)  
      {  
         dd*=10;  
      }  
      tempnum=num*dd;  
      tempnum=Math.round(tempnum);  
	  var res = tempnum/dd
	  var ling = ""
	  for(var i=0;i<n;i++)
	     ling += "0"
	  if(String(res).indexOf(".",0)==-1)
	     return(String(res)+"."+ling)
	  else if(String(res).lastIndexOf(".")==String(res).length-2)
	     return(String(res)+"0")
	  else
         return(tempnum/dd);  
   }