if (document.images) {
bk1off = new Image
bk2off = new Image
bk3off = new Image
bk4off = new Image
bk5off = new Image
bk6off = new Image
bk7off = new Image

bk1on = new Image
bk2on = new Image
bk3on = new Image
bk4on = new Image
bk5on = new Image
bk6on = new Image
bk7on = new Image

bk1off.src = "images/history_bk1.gif"
bk2off.src = "images/history_bk2.gif"
bk3off.src = "images/history_bk3.gif"
bk4off.src = "images/history_bk4.gif"
bk5off.src = "images/history_bk5.gif"
bk6off.src = "images/history_bk6.gif"
bk7off.src = "images/history_bk7.gif"

bk1on.src = "images/history_bk1_r.gif"
bk2on.src = "images/history_bk2_r.gif"
bk3on.src = "images/history_bk3_r.gif"
bk4on.src = "images/history_bk4_r.gif"
bk5on.src = "images/history_bk5_r.gif"
bk6on.src = "images/history_bk6_r.gif"
bk7on.src = "images/history_bk7_r.gif"

}
else {

bk1off =  " "
bk2off =  " "
bk3off =  " "
bk4off =  " "
bk5off =  " "
bk6off =  " "
bk7off =  " "

bk1on =  " "
bk2on =  " "
bk3on =  " "
bk4on =  " "
bk5on =  " "
bk6on =  " "
bk7on =  " "

document.bk1 =  " "
document.bk2 =  " "
document.bk3 =  " "
document.bk4 =  " "
document.bk5 =  " "
document.bk6 =  " "
document.bk7 =  " "

}