Solved

Hide/show span element with Javascript on page resize

Posted on 2013-06-17
4
757 Views
Last Modified: 2013-11-19
In my HTML I have:
<span name="manual_icons_portrait" align="center" style="display:none;">
html...
</span>

and

<span name="manual_icons_landscape" align="center" style="display:block;">
html...
</span>

I then use Javascript to detect the page size to then show or hide the appropriate span element:
//alert(browser_width);
if ((window.innerWidth || document.documentElement.clientWidth) < 1500)
{
      document.getElementsByName('manual_icons_portrait').style.display = 'block';
      document.getElementsByName('manual_icons_landscape').style.display = 'none';
}
else
{
      document.getElementsByName('manual_icons_portrait').style.display = 'none';
      document.getElementsByName('manual_icons_landscape').style.display = 'block';
}

Although it does not work and in my Firefox JS debugger it always says getElementsByName(...) is null or undefined.

So I thought it was because the JS was called before the HTML was rendered therefore not referring it to anything i.e. no CSS to change with the function as the CSS does not exist yet. I put the JS after the HTML - after the closing body tag - still to no avail.

Please say how this would work and switch between the span elements.
0
Comment
Question by:Johny_Brav0
  • 3
4 Comments
 
LVL 28

Accepted Solution

by:
Pravin Asar earned 500 total points
ID: 39254626
window.onresize = function(event) {
   // Your Code
}

The onresize event occurs when the size of an window has changed

Look at the implementation at

http://www.javascriptjournal.com/tutorials/windetails.htm
0
 
LVL 28

Assisted Solution

by:Pravin Asar
Pravin Asar earned 500 total points
ID: 39254631
Also use getElementById  instead of   getElementsByName

Assign the id="ElementID"
0
 

Author Comment

by:Johny_Brav0
ID: 39259888
Code that works - off of Google then Stack Overflow.

Thanks for the help.

// Detect whether device supports orientationchange event, otherwise fall back to
// the resize event.
var supportsOrientationChange = "onorientationchange" in window,
      orientationEvent = supportsOrientationChange ? "orientationchange" : "resize";

window.addEventListener(orientationEvent, function()
{
      //alert('screen:' + window.orientation + " " + screen.width);
      
      var manual_icon_portrait_var = document.getElementById('manual_icons_portrait');
      var manual_icon_landscape_var = document.getElementById('manual_icons_landscape');

      if ((manual_icon_portrait_var.style.display == 'none') && (screen.width == 800))
      {
            manual_icon_portrait_var.style.display = 'block';
            manual_icon_landscape_var.style.display = 'none';
      }
      else
      {
            manual_icon_portrait_var.style.display = 'none';
            manual_icon_landscape_var.style.display = 'block';
      }

}, false);
0
 
LVL 28

Expert Comment

by:Pravin Asar
ID: 39260993
Here is a simple code.

<html>
      <head>
<script>          
  function doOnOrientationChange()
  {
        // Look the orientation
    switch(window.orientation)
    {  
      case -90:
      case 90:
        alert('landscape');
        break;
      default:
        alert('portrait');
        break;
    }
    // Alternate way
    if (screen.height > screen.width){
          alert("Portrait!");
      }
      else {
        alert('Landscape');            
      }
  }
  window.addEventListener('onorientationchange', doOnOrientationChange);

  // Initial execution if needed
  doOnOrientationChange();
</script>
            
      </head>
      <body onload="doOnOrientationChange()">
<h1>Simple code</h1>
            
      </body>
</html>
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