Document Will Save Question

I have Document Will save question. I'm just trying run this script that will prompt an app. alert if the a text box is visible, let me know what I'm doing wrong here, I'm new to adobe forms, so thanks for any help.

var a = this.getField("Text11");

if (Text11 == display.visible)

    app.alert({CMsg:"remove all text", oCheckbox:true});