Question

For some reason the spinner object is working only if it is defined inside the startSpin() function.

This is the non-working code:

<script type="text/javascript" src="resources/js/spin.js"></script>
    <script type="text/javascript">
        var opts = {
            lines: 18, // The number of lines to draw 
            length: 40, // The length of each line
            top: 'auto', // Top position relative to parent in px
            left: 'auto' // Left position relative to parent in px
        };

         // -- not support ? 
        var target = document.getElementById('spin');
        var spinner = new Spinner(opts).spin(target);
        // -- ???
        function startSpin()
        {
            spinner.start();   
        }
        function stopSpin()
        {
            spinner.stop();  
        }

        function showStatus() {
            startSpin();
            statusDialog.show();
        }

        function hideStatus() {
            stopSpin();
            statusDialog.hide();
        }
    </script>
    <h:form id="testfm">
        <p:commandButton id="start" type="submit" 
                         ajax="false" 
                         value="test" 
                         actionListener="#{bean.test}" 
                         onclick="PrimeFaces.monitorDownload(showStatus, hideStatus)"/>
        <p:dialog modal="true" 
                  widgetVar="statusDialog" 
                  showHeader="false"
                  draggable="false" 
                  closable="false" 
                  resizable="false">
            <div id="spin" class="spinner"/>
        </p:dialog>
    </h:form>

the spinner is working only when it is defined inside the spinStart function

I try to play with the script position but still get the same message
any idea why?

Thanks

Answer 1

You you run document.getElementById('spin') outside of that function, the element with id=spin has not been created yet, so you are giving a null value to the spinner. If you create it inside startSpin, it is in response to a click event from the user, so the DOM has likely been built at that point and the element exists. Here is a workaround:

    var spinner;  //Lave the variable out here so both functions can see it

    function startSpin() {
        var target = document.getElementById('spin');
        spinner = new Spinner(opts).spin(target);  //Actually create it here, when the element exists
        spinner.start();   
    }
    function stopSpin() {
        spinner.stop();  
    }

You could also leave the code as it is and put it at the end of your document, just before the </body> tag.