html - how to access multiple select array data in javascript -

i have multiple select box , want access selected data in javascript. here code:

<form onsubmit="return false;" id="multisel">   <select name="a[]" id="a" multiple style="width:350px;" tabindex="4">     <option value="pedro">1</option>     <option value="alexis">2</option>     <option value="messi">3</option>     <option value="villa">4</option>     <option value="andres">5</option>     <option value="sergio">6</option>     <option value="xavi">7</option>   </select>    <button id="btn1" onclick="ajaxmultiselect()" type="submit" class="btn btn-primary">save changes</button>    <p id="status"></p> </form> 

here code have tried far :

<script>     function ajaxmultiselect(){   var input  = [];   input = document.getelementbyid("a").value;   var status = _("status");   if(input == ""){     status.innerhtml = "fill out of form data";   }else {     status.innerhtml = input;   } } </script> 

when run code gives first value. tried access values in php , works fine, passes value array in php. why isn't doing same javascript?

i tried run loop length of value calculates length of first selection only. want display values selected.

any appreciated.

you can following:

function getselectedoptions(element) {     // validate element     if(!element || !element.options)         return []; //or null?      // return html5 implementation of selectedoptions instead.     if (element.selectedoptions)         return element.selectedoptions;      // here because browser doesn't have html5 selectedoptions     var opts = element.options;     var selectedoptions = [];     for(var = 0; < opts.length; i++) {          if(opts[i].selected) {              selectedoptions.push(opts[i]);          }     }     return selectedoptions; } 

and change ajaxmultiselect() call this:

input = getselectedoptions(document.getelementbyid("a")); 

you have iterate values tho.