title: Disable submit button on a separate php file when timer runs down on javascript file
body: <p>I have a php form and a separate javascript file called countdown.js that runs down a timer to a target date and then displays a message, ive tried various things to get the submit button to disable when this has finished.</p>
  
  <p>This is my form </p>
  
  <pre><code>&lt;form id="MakeBid" action="MakeBid.php" method="POST"&gt;
  &lt;input type="hidden" name="propertyID" value ="1"/&gt;
  &lt;div&gt;Bid Now &lt;input type="text" name="pricesoldfor"/&gt;&lt;/div&gt; 
  &lt;input id = "submit" input type="submit" value="Submit" /&gt; 
  &lt;/form&gt;
  </code></pre>
  
  <p>This is my java code</p>
  
  <pre><code>function calcage(secs, num1, num2) {
      s = ((Math.floor(secs / num1)) % num2).toString();
      if (LeadingZero &amp;&amp; s.length &lt; 2) s = "0" + s;
      return "&lt;b&gt;" + s + "&lt;/b&gt;";
  }
  
  function CountBack(secs) {
      if (secs &lt; 0) {
          document.getElementById("cntdwn").innerHTML = FinishMessage;
  
  
          return;
      }
      DisplayStr = DisplayFormat.replace(/%%D%%/g, calcage(secs, 86400, 100000));
      DisplayStr = DisplayStr.replace(/%%H%%/g, calcage(secs, 3600, 24));
      DisplayStr = DisplayStr.replace(/%%M%%/g, calcage(secs, 60, 60));
      DisplayStr = DisplayStr.replace(/%%S%%/g, calcage(secs, 1, 60));
      document.getElementById("cntdwn").innerHTML = DisplayStr;
      if (CountActive) setTimeout("CountBack(" + (secs + CountStepper) + ")", SetTimeOutPeriod);
  }
  
  function putspan(backcolor, forecolor) {
      document.write("&lt;span id='cntdwn' style='background-color:" + backcolor + "; color:" + forecolor + "'&gt;&lt;/span&gt;");
  }
  
  if (typeof(BackColor) == "undefined") BackColor = "white";
  if (typeof(ForeColor) == "undefined") ForeColor = "black";
  if (typeof(TargetDate) == "undefined") TargetDate = "12/31/2020 5:00 AM";
  if (typeof(DisplayFormat) == "undefined") DisplayFormat = "%%D%% Days, %%H%% Hours, %%M%% Minutes, %%S%% Seconds.";
  if (typeof(CountActive) == "undefined") CountActive = true;
  if (typeof(FinishMessage) == "undefined") FinishMessage = "";
  if (typeof(CountStepper) != "number") CountStepper = -1;
  if (typeof(LeadingZero) == "undefined") LeadingZero = true;
  CountStepper = Math.ceil(CountStepper);
  if (CountStepper == 0) CountActive = false;
  var SetTimeOutPeriod = (Math.abs(CountStepper) - 1) * 1000 + 990;
  putspan(BackColor, ForeColor);
  var dthen = new Date(TargetDate);
  var dnow = new Date();
  if (CountStepper &gt; 0) ddiff = new Date(dnow - dthen);
  else ddiff = new Date(dthen - dnow);
  gsecs = Math.floor(ddiff.valueOf() / 1000);
  CountBack(gsecs);​
  </code></pre>