How should I design a form that is easy to use and understand that has a few textfields for currency?
Should the currency symbol be put outside or in the textfield?
One variant is to show the currency symbol inside the textfield when the textfield doesn't have focus. And when the textfield get focus the currency symbol is removed and only a decimal number is shown in the textfield.
I think that is easy to understand. But what to do if the focus is lost and the input is invalid? I guess it should be left in the invalid state but with some colors that indicate that the input is invalid.
Are there any recommendations for this? Are there any practice for using the currency symbol within or outside the textfield in the financial world?