JavaScript form function toFixed only displaying one digit in some cases

[rtpt-romankarwacik]

Attach (recommended) or Link to PDF file here:
test.pdf

Configuration:

• Web browser and its version: Firefox 121.0.1
• Operating system and its version: Fedora 39
• PDF.js version: PDF.js: 4.0.240 [ffbfd68]
• Is a browser extension: Yes? pdf.js it integrated into Firefox

Steps to reproduce the problem:

1. Open the attached PDF file
2. Type a number into the textfield

What is the expected behavior?
For example in Chromium or Okular the resulting Numbers have a fixed number of decimal digits (3):

What went wrong?
In Firefox, only one decimal digit is shown for one value, while the other is properly displayed:

The underlying latex code used to produce the PDF:

\documentclass{article}
\usepackage{hyperref}

\begin{document}
\begin{Form}
\TextField[name=f1]{\null} $\cdot 0.3 =$
\TextField[calculate={
event.value = (parseInt(this.getField('f1').value) * 0.3).toFixed(3);
},readonly=true,name=f1calc]{\null}
\TextField[calculate={
this.getField('f1').value;
event.value = (0.33333).toFixed(3);
},readonly=true,name=f2calc]{\null}
\end{Form}
\end{document}

[Snuffleupagus]

The formatting seems to be clobbered at the following line, however I don't know what (if any) effect simply keeping all existing decimal places would have in the general case?

pdf.js/src/scripting_api/field.js

Line 261 in f8e3c79

this._value = !isNaN(_value) ? parseFloat(_value) : value;

[calixteman]

Yep it's because we're using the value field which should be a number when it's a "number" in the Calculate process:

pdf.js/src/scripting_api/event.js

Line 315 in f8e3c79

runCalculate(source, event) {