如何在html中维护单个字段的两个值

I have a requirement, where i need to show rounded decimal value for the fields in the page. But if user doesn't change the field's value then i need to post the original value of field instead of rounded value and my external library will be called with this posted values. For example if a have a field 'Initial Temperature' and its value 12.892433 in database, when i populate the field in the page it will be 12.9. Now if user doesnt change this value then i need to post the actual value which is 12.892433.I have a requirement, where i need to show roun