How to hide the Imagefield using java script?

i am  trying to hide the image  field  using java scipt?

i  written this  code in calculate* event and  it's not working in my adobe live cycle designer..?

Could you please clarify this  issue?

var x= this.rawValue;

x = 100;

if(x >= 0 && x <=10000)

{

ImageField1.presence = "visible";

ImageField2.presence = "hidden";

} else

if(x >= 10001 && x <= 100000)

{

ImageField1.presence = "hidden";

}