Remove red colour border

Hi everyone!
I have write a script for a checkbox for required fields.
here is my script:

var c =this.getField("cb1");
if(c.isBoxChecked(0))
{
app."Fields with red border are required!",3);
var f = this.getField("Text1");
var b = this.getField("Text2");
f.required = true;
f.strokeColor=color.red;
b.required = true;
b.strokeColor=color.red;
}
else
{
f.strokeColor=color.transparent;
b.strokeColor=color.transparent;

}
It is working fine but I have a problem!
After when I insert the data into required filds how can I remove the red stroke border?
Again thanks for your help!!!