js 中的数字（带有两位小数的浮点数）计算

知识点：将字符转换成数字，并进行准确计算，保留相应的位数！

function modifyOrderItemCount(sales_id, count_variable,sales_price)

{
var count = util.$("count_"+sales_id).innerHTML;


var totleCount = util.$("totleCount").innerHTML;
var salesprice = sales_price;

if(count_variable == "-1" && count == "0")
{
return;
}
if(count_variable == "-1")
{
util.$("count_"+sales_id).innerHTML = parseInt(count) - 1;
if(totleCount != 0)
{
util.$("totleCount").innerHTML=(parseFloat(totleCount) - parseFloat(salesprice)).toFixed(2);
}
}
else
{
util.$("count_"+sales_id).innerHTML = parseInt(count) + 1;
util.$("totleCount").innerHTML=(parseFloat(totleCount) + parseFloat(salesprice)).toFixed(2);
}
}