![Simple example of JavaScript to calculate time difference in a PDF in hours and minutes – PDF Studio Knowledge Base Simple example of JavaScript to calculate time difference in a PDF in hours and minutes – PDF Studio Knowledge Base](https://kbpdfstudio.qoppa.com/wp-content/uploads/Javascript-3.png)
Simple example of JavaScript to calculate time difference in a PDF in hours and minutes – PDF Studio Knowledge Base
![Simple example to add custom JavaScript calculations to form fields in a PDF – PDF Studio Knowledge Base Simple example to add custom JavaScript calculations to form fields in a PDF – PDF Studio Knowledge Base](https://kbpdfstudio.qoppa.com/wp-content/uploads/textfields.png)
Simple example to add custom JavaScript calculations to form fields in a PDF – PDF Studio Knowledge Base
![PDF22: Indicating when user input falls outside the required format or values in PDF forms | WAI | W3C PDF22: Indicating when user input falls outside the required format or values in PDF forms | WAI | W3C](https://www.w3.org/WAI/WCAG21/Techniques/pdf/img/jscript.jpg)
PDF22: Indicating when user input falls outside the required format or values in PDF forms | WAI | W3C
![How to calculate data grid column (ex: addition) using javascript Calculated Value · Issue #687 · formio/formio · GitHub How to calculate data grid column (ex: addition) using javascript Calculated Value · Issue #687 · formio/formio · GitHub](https://user-images.githubusercontent.com/1378636/48625108-3f59fa00-e9d4-11e8-83e8-8e0569eec38f.png)