if (document.images) {

b1 = new Image
b2 = new Image
b3 = new Image
b4 = new Image
b5 = new Image
b6 = new Image
b7 = new Image
b8 = new Image
b9 = new Image
b10 = new Image
b11 = new Image
b12 = new Image
b13 = new Image
b14 = new Image

b1.src = "Assets/images/button01.gif"
b2.src = "Assets/images/subscribe_off.gif"
b3.src = "Assets/images/button03.gif"
b4.src = "Assets/images/button04.gif"
b5.src = "Assets/images/button05.gif"
b6.src = "Assets/images/button06.gif"
b7.src = "Assets/images/button07.gif"
b8.src = "Assets/images/button08.gif"
b9.src = "Assets/images/button09.gif"
b10.src = "Assets/images/button10.gif"
b11.src = "Assets/images/wipesurface_bu.gif"

b1On = new Image
b2On = new Image
b3On = new Image
b4On = new Image
b5On = new Image
b6On = new Image
b7On = new Image
b8On = new Image
b9On = new Image
b10On = new Image
b11On = new Image
b12On = new Image
b13On = new Image
b14On = new Image

b1On.src = "Assets/images/button01_on.gif"
b2On.src = "Assets/images/subscribe_on.gif"
b3On.src = "Assets/images/button03_on.gif"
b4On.src = "Assets/images/button04_on.gif"
b5On.src = "Assets/images/button05_on.gif"
b6On.src = "Assets/images/button06_on.gif"
b7On.src = "Assets/images/button07_on.gif"
b8On.src = "Assets/images/button08_on.gif"
b9On.src = "Assets/images/button09_on.gif"
b10On.src = "Assets/images/button10_on.gif"
b11On.src = "Assets/images/wipesurface_buon.gif"

}

function chgImg(imgField,newImg) {
   if (document.images) {
       document[imgField].src= eval(newImg + ".src")
   }
 }