How to Use an Acrobat JavaScript LEFT Formula Equivalent in PDF
Question details
The user needs to create a calculated testing ID in a fillable PDF by extracting specific characters from first-name, last-name, and birthday fields using an Acrobat JavaScript equivalent to the LEFT formula.
- Product
- Device & OS
- not provided
- Scenario
- Setting up a fillable PDF form that automatically generates a unique testing ID based on substrings extracted from the user's input in other text fields.
- Observed behavior
- JavaScript is required to extract a set number of characters from the beginning or end of multiple string values and concatenate them into a target ID field.
Ensure your PDF form already contains the exact text fields (e.g., 'First Name', 'Last Name', and 'Birthday') necessary for the calculation before you apply the custom script to the target ID field.
Use the JavaScript substr() Method in Custom Calculation Scripts
Since JavaScript does not have a native 'LEFT' function like Excel, you can use the substr() method to extract characters from specific positions in your PDF form fields.
The substr() method allows you to define a starting position and the number of characters to extract. For a 'LEFT' formula equivalent, you start at index 0. You can also use a negative starting index to extract characters from the end of a string, acting as a 'RIGHT' formula equivalent.
Open your PDF form editor, right-click the target field where you want the ID to appear (e.g., 'Testing ID'), and select 'Properties' from the context menu.
In the Properties dialog box, click on the 'Calculate' tab to view calculation options.
Select the 'Custom calculation script' radio button, click 'Edit', and enter this script: event.value = (this.getField('Last Name').valueAsString.substr(0,3) + this.getField('First Name').valueAsString.substr(0,2) + this.getField('Birthday').valueAsString.substr(-2)).toUpperCase();
Click 'OK' to save the script and close the Properties window. Test the form by typing values into the Name and Birthday fields to ensure the ID automatically generates (e.g., producing SMIJA80).
Create and Manage PDF Forms with WPS Office
WPS Office provides a comprehensive PDF editor that allows you to effortlessly create fillable forms, manage text fields, and configure interactive document properties.
- 1. Open PDF Form in WPS Office: Launch WPS Office and open your existing PDF document or create a new one.
- 2. Access Form Tools: Navigate to the 'Form' tab on the top ribbon to access the form editing toolset.
- 3. Add Necessary Text Fields: Click 'Text Field' and draw boxes for the Last Name, First Name, Birthday, and the target ID fields.
- 4. Configure Properties: Double-click the target ID field to open its properties, where you can modify field names, appearance, and formats to ensure compatibility with your data.
Frequently Asked Questions
Why isn't my PDF JavaScript calculation updating automatically?
Ensure that the calculation order is set correctly in your PDF form properties. The source fields (like Name and Birthday) must be processed before the target ID field. You can adjust the calculation order in the form editing menu.
Can I use the substring() method instead of substr() in Acrobat JavaScript?
Yes, substring(0,3) can also be used to extract the first three characters, serving as a LEFT formula equivalent. However, substr() is often preferred when you also need to extract from the end of a string using a negative starting index.
How do I handle empty fields in my PDF calculation script?
To prevent errors or partially generated IDs when the form is incomplete, wrap your extraction script in an 'if' statement that checks if the source fields are empty (e.g., if(this.getField('Last Name').valueAsString !== '') before generating the ID.
