Checkbox value Visibility
===

i have this code to say if a check box is checked then display a value from hidden. What i would like is for this code to do the follow,

Once one value is clicked the opposing value disappears. and further on once the submit button is pressed, could it possibly store this value in a DB or something?

    <script>
      function toggleVisibility(id) {
       var el = document.getElementById(id);
        
       if (el.style.visibility=="visible") {
              el.style.visibility="visible";
        
         }
         else {
              el.style.visibility="visible";
         }
          
     }
        
    </script>
    
    <label for="chkemployment">Employment</label>
    <input type="checkbox" id="chkemployment" onChange="toggleVisibility('imgemployment');" /><br/>
    
    <label for="chkemployment">Extra</label>
    <input type="checkbox" id="chkemployment" onChange="toggleVisibility('imgemployment');" />
    
    
    <label for="chkpopulation">Population</label>
    <input type="checkbox" id="chkpopulation"  onChange="toggleVisibility('imgpopulation');" />
    <hr />
    
    <span id="imgemployment" value="Hello" style="visibility:hidden"> HELLO </span>
    <span id="imgpopulation" style="visibility:hidden"> Bye </span>


