get field value from drupal in javascript code

Hello
I created pdf protected with password. They are uploaded to drupal and the password is saved in a field pdf_password in drupal.
I would like the pdf to open with pdf.js without having to ask for the password. For this i need to get the value of the field password pdf_password in the file pdf.js/web/viewer.js: instead of 123 to get the value of the field password pdf_password :

if (typeof file === 'string') {
this.setTitleUsingUrl(file);
parameters.url = file;
parameters.password = '123';
} else if (file && 'byteLength' in file) {
parameters.data = file;
parameters.password = '123';
} else if (file.url && file.originalUrl) {
this.setTitleUsingUrl(file.originalUrl);
parameters.url = file.url;
parameters.password = '123';
}

Thank you