javascript function "visibile Invisible()"

Javascript function:
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function enabledDisabled(chkBox,form)
{
if(chkBox.checked)
{
form.enableTxtBox.disabled=false
}
else
{
form.enableTxtBox.disabled=true
}
}

function visibleInvisible(chkBox,form)
{
if(chkBox.checked)
{
form.visibleTxtBox.style.visibility="visible"
}
else
{
form.visibleTxtBox.style.visibility="hidden"
}
}