How to make content drop to bottom

Ionic Framework
1

I’m try to make something like, if someone click in textarea, my scrool go to the bottom i make something like this:

 addKeyboardListeners() {
    this.keybaordShowSub = this.keyboard.onKeyboardShow().subscribe(e => {
      this.updateScroll("keybaord show", this.scrollTimeout);
      let newHeight =
        e["keyboardHeight"] + this.textareaHeight - this.initialTextAreaHeight;
      let marginBottom = newHeight + 44 + "px";
      this.renderer.setElementStyle(
        this.scrollContentElement,
        "marginBottom",
        marginBottom
      );
      this.renderer.setElementStyle(
        this.footerElement,
        "marginBottom",
        e["keyboardHeight"] + "px"
      );
      /*this.updateScroll("keybaord show", this.scrollTimeout);*/
      // console.log("keybaordShowSub");
      this.updateScroll("keybaord show", 300);
      this.updateScroll("keybaord show", 500);
    });
  }

but in IOS sometimes, if have a lot of item’s in content, if i click in text area, all html texts get invisible and only css its apply, can someone help with this?