javascript doing nothing
<p>i am trying to make a finish time in a line of text update depending on the length of time selected in the drop down box relative to the start time.</p>

<p>so if the start time was 13:00 and the user selects 1 hour the finish time would update to 14:00</p>

<p>I dont have a  clue what i am doing right or wrong since i dont know the first thing about javascript.</p>

<pre><code>  &lt;script type='text/javascript'&gt;
         function changeText(){
            var option=document.getElementById('time').value;
               if(option=='30'){
                     document.getElementById('field').value='".date(strtotime("$finishtime + 30 minutes"))."';
                               }

              else if(option=='60'){
                     document.getElementById('field').value='".date(strtotime("$finishtime + 60 minutes"))."';
                               }
             }
  &lt;/script&gt;
</code></pre>

<p>i dont seem to be getting any errors in the debugger and the script does nothing.</p>

<pre><code>&lt;a&gt;Booking For ".$start." - &lt;/a&gt;&lt;a id='field'&gt;".$finishtime."&lt;/a&gt;&lt;a&gt; on ".$date."&lt;/a&gt;

         &lt;form enctype='multipart/form-data' method='post'&gt;
                 &lt;a class='1'&gt;Session Length&lt;/a&gt;
                       &lt;select name='time' id='time' onchange='changeText();'&gt;
                             &lt;option selected='selected'&gt;&lt;/option&gt;
                             &lt;option id='30' value='30'&gt;30 mins&lt;/option&gt;
                             &lt;option id='60' value='60'&gt;1 Hour&lt;/option&gt;
                       &lt;/select&gt;
</code></pre>
