Shiny - how to make footer stick to bottom of page

run.md

run by doing

library(shiny)
runGist('5694313')

server.r

library(shiny)

## Set up server output
shinyServer(function(input, output) {
  
  foo <- reactive({
    input$num
  })
  
  output$plot <- renderPlot({
    number <- foo()
    plot(rnorm(number))
  })
  
  output$plot2 <- renderPlot({
    number <- foo()
    plot(rnorm(number))
  })
  
})

ui.r

library(shiny)

shinyUI(pageWithSidebar(
  
  headerPanel(title=HTML("TaxaViewer - <i>Explore data on your species list</i> "), windowTitle="TaxaViewer"),
  
  sidebarPanel(
    wellPanel(
      h4(strong("Do something")),
      textInput(inputId="num", label="Number", value=I(10^5))
    )
  ),
  
  mainPanel(
    tags$style(type = 'text/css', 
               "footer{position: absolute; bottom:5%; left: 33%; padding:5px;}"
    ),
    
    tabsetPanel(
      tabPanel("output", 
               plotOutput("plot"),
               HTML('<footer>
                      <img src="http://amor.cms.hu-berlin.de/~huangrui/images/softwares/Rlogo.png", height="120", width="120"</img>
                    </footer>')
      ),
      tabPanel("output", 
               plotOutput("plot2"),
               HTML('<footer>
                      <img src="http://jasontheodor.com/wp-content/uploads//2012/02/things.jpg", height="120", width="120"</img>
                    </footer>')
               )
    ))
))

Add these lines inside the dashboard body

tags$footer(title="Your footer here", align = "right", style = "
position:absolute;
bottom:0;
width:100%;
height:50px; /* Height of the footer */
color: white;
padding: 10px;
background-color: black;
z-index: 1000;"
)