Change text fields from white to transparent after filled in

[geigreg]

I have several text fields that I want to be white but once the user fills them in I need them to be transparent. I've tried several things I have seen here on the forum but can't get any of them to work. Help?

[ls_rbls · Accepted solution]

Another example of a much more simpler and elegant custom format script (in my opinion) that fits in a single line would be:

event.target.fillColor  =  event.target.value.length > 0 ? color.red : color.transparent;

For this other example I used a variation of the following script :

var f = event.target; /* field that the event occurs at */
f.target.textColor = event.value < 0 ? color.red : color.black;

Which is explained in greater detail in the Adobe Acrobat SDK JavaScript API, 
JavaScript™ for Acrobat® API -- "Reference color methods" on page 164

• https://opensource.adobe.com/dc-acrobat-sdk-docs/acrobatsdk/pdfs/acrobatsdk_jsapiref.pdf

[ls_rbls]

This may be achieved in different ways with a JavaScript script.

In my example below I used a Custom Format Script:

if (event.willCommit) {

var f = event.target;
var g = event.value;

if (g =="") {

    f.fillColor = color.white;

} else {

if (g !="") {

   f.fillColor = color.transparent;

    }
  }

}

[ls_rbls · Accepted solution]

Another example of a much more simpler and elegant custom format script (in my opinion) that fits in a single line would be:

event.target.fillColor  =  event.target.value.length > 0 ? color.red : color.transparent;

For this other example I used a variation of the following script :

var f = event.target; /* field that the event occurs at */
f.target.textColor = event.value < 0 ? color.red : color.black;

Which is explained in greater detail in the Adobe Acrobat SDK JavaScript API, 
JavaScript™ for Acrobat® API -- "Reference color methods" on page 164

• https://opensource.adobe.com/dc-acrobat-sdk-docs/acrobatsdk/pdfs/acrobatsdk_jsapiref.pdf

[Nesa Nurani · Accepted solution]

This won't work for numbers though, also change 'red' to 'white' and change place transparent : white.

EDIT: Try like this: event.target.fillColor = event.target.value != "" ? color.transparent : color.white;

[geigreg]

This worked well for me. Thank you!