Toggle an image when checkbox is checked/unchecked

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Toggle an image when checkbox is checked/unchecked

bsbarker

10:57 am on May 17, 2010 (gmt 0)

I have six checkboxes in my form. When each one is checked/unchecked I'd like to toggle an image related to that checkbox. Basically, I need the effect that would be achieved by using "oncheck" and "onuncheck" events (would be nice if those existed!) to make the images hidden and visible.

For each of the six checkboxes, I'm currently using "onfocus" and "onblur" events to toggle each image:

<input type="checkbox" onfocus="document.getElementById('[i]myImageId[/i]').style.visibility='hidden';" onblur="document.getElementById('[i]myImageId[/i]').style.visibility='visible';">

But of course the image becomes visible again with the "onblur" event, even if the box is still checked. And of course if I exclude the "onblur" event then it does not toggle back to the original image when the box is checked and then unchecked. Either way, not exactly what I'm going for.

Any suggestions?

Readie

12:44 pm on May 17, 2010 (gmt 0)

Try writing a function to toggle it based on a variable, maybe something like:

var x = 1;
function toggleimage() {
  if(x == 1) {
    // SHOW IMAGE CODE
    x = 2;
  } else {
    // HIDE IMAGE CODE
    x = 1;
  }
}

And then the checkbox looks like:

<input type="checkbox" onchange="toggleimage()">

Could even modify that to use the same function to toggle multiple images, although that'll get a bit more complicated:

<input type="checkbox" onchange="toggleimage('imageID')">

var x = new Array();
function toggleimage(theid) {
  if(!x[theid]) {
    x[theid] = 1;
  }
  if(x[theid] == 1) {
    // SHOW IMAGE CODE
    x[theid] = 2;
  } else {
    // HIDE IMAGE CODE
    x[theid] = 1;
  }
}

daveVk

12:50 pm on May 17, 2010 (gmt 0)

rocknbil

5:58 pm on May 17, 2010 (gmt 0)

Remember that hidden and visible will still take up space in your document, you may want to use the display property, setting it to none to hide, block to display, instead.

If you don't mind it taking up the space, just set the src of the image element. Tested example.


<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01  
Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 
<html lang="en"> 
<head> 
 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 
 <title>Swap image</title> 
<script type="text/javascript"> 
window.onload=function() { attachBehaviors(); } 
function attachBehaviors() { 
 // only doing one here, but you can add others 
 if ( 
 document.getElementById('toggle_chk') && 
 document.getElementById('my_img') 
 ) { 
 // So JS is "aware" of the element style 
 document.getElementById('my_img').style.display='block'; 
 // Attach the behavior 
 document.getElementById('toggle_chk').onclick=function() {  
 toggle_image(this);  
 }; 
 } 
} 
// 
function toggle_image(chk) { 
 // already checked for my_img 
 // if you want to hide it . . .  
 document.getElementById('my_img').style.display=(chk.checked)?'block':'none'; 
 // if you just want to swap src 
 //var src=(chk.checked)?'my_image.jpg':''; 
 //document.getElementById('my_img').src=src; 
} 
</script> 
</head> 
<body> 
<form action=""> 
<p><input type="checkbox" name="toggle_chk" id="toggle_chk" value="1" checked> 
<label for="toggle_chk">Image on/off</label></p> 
<p><img src="my_image.jpg" id="my_img"></p> 
</form> 
</body> 
</html>

bsbarker

5:55 am on May 18, 2010 (gmt 0)

It turns out that daveVk's works great and is a much simpler solution than I expected! And since I don't need to worry about taking up space for what I'm doing, it will be perfect.

Much obliged to you all for your suggestions!