function keyVisibility(isVisible) {
        if (isVisible === true) {
            $('#cacheKey-row').show()
            $('#help-per').show()
            $('#caspan').hide()
        } else {
            $('#cacheKey-row').hide()
            $('#help-per').hide()
            $('#caspan').show()
        }
    }
If caching my a msg.xxxxx value, show/hide bits of help text
@param {boolean} isVisible Whether the Cache By field is visible