function toMoney(m)         //common function
    {
        return Math.floor(m*100 + 0.5)/100.0;
    }

    function isNum(m)         //common function
    {
        return m*1 == m;
    }

	var clk_num = 0;
    function numFld(f)         //common function
    {
        if(!isNum(f.value))
        {
            alert("请输入数字!");
            f.focus();
			if(++clk_num>2){
				f.value = "";
				clk_num = 0;
			}
        }else{
			clk_num = 0;
		}
    }