parseFloat(): why a decimal comma is not recognized automatically

Useful to know

Number.parseFloat() reads the permissible beginning of numeric text. For example, "3.5kg" gives 3.5, while "3,5" gives 3: the comma is not a decimal separator in this syntax . [1]

In the case of a Bulgarian form, first determine the authorized format and the processing of the separators. Random replacement of all commas can also be mistaken for separators for thousands. Parsing and validation must work together. Don't take the non-zero result as proof that the entire user input is understood correctly.