The spec for this action:
https://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf#G11.2111850
An example of a form using this action:
https://www2.illinois.gov/rev/forms/reg/Documents/reg-1-mr.pdf
element.addEventListener("blur", blurListener);
      }
      if (this.data.maxLen !== null) {
        element.maxLength = this.data.maxLen;
      }
      if (this.data.comb) {
        const fieldWidth = this.data.rect[2] - this.data.rect[0];
        const combWidth = fieldWidth / this.data.maxLen;
        element.classList.add("comb");
        element.style.letterSpacing = `calc(${combWidth}px - 1ch)`;
      }
    } else {
      element = document.createElement("div");
      element.textContent = this.data.fieldValue;
      element.style.verticalAlign = "middle";
      element.style.display = "table-cell";
    }
    this._setTextStyle(element);
    this._setBackgroundColor(element);
    this.container.appendChild(element);
    return this.container;
  }
  /**
   * Apply text styles to the text in the element.
   *
   * @private
   * @param {HTMLDivElement} element
   * @memberof TextWidgetAnnotationElement
   */
  _setTextStyle(element) {