En ese caso, probá así:
Código PHP:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Documento sin título</title>
<script>
// DF1.1 :: domFunction
// *****************************************************
// DOM scripting by brothercake -- http://www.brothercake.com/
// GNU Lesser General Public License -- http://www.gnu.org/licenses/lgpl.html
//******************************************************
//DOM-ready watcher
function domFunction(f, a)
{
//initialise the counter
var n = 0;
//start the timer
var t = setInterval(function()
{
//continue flag indicates whether to continue to the next iteration
//assume that we are going unless specified otherwise
var c = true;
//increase the counter
n++;
//if DOM methods are supported, and the body element exists
//(using a double-check including document.body, for the benefit of older moz builds [eg ns7.1]
//in which getElementsByTagName('body')[0] is undefined, unless this script is in the body section)
if(typeof document.getElementsByTagName != 'undefined' && (document.getElementsByTagName('body')[0] != null || document.body != null))
{
//set the continue flag to false
//because other things being equal, we're not going to continue
c = false;
//but ... if the arguments object is there
if(typeof a == 'object')
{
//iterate through the object
for(var i in a)
{
//if its value is "id" and the element with the given ID doesn't exist
//or its value is "tag" and the specified collection has no members
if
(
(a[i] == 'id' && document.getElementById(i) == null)
||
(a[i] == 'tag' && document.getElementsByTagName(i).length < 1)
)
{
//set the continue flag back to true
//because a specific element or collection doesn't exist
c = true;
//no need to finish this loop
break;
}
}
}
//if we're not continuing
//we can call the argument function and clear the timer
if(!c) { f(); clearInterval(t); }
}
//if the timer has reached 60 (so timeout after 15 seconds)
//in practise, I've never seen this take longer than 7 iterations [in kde 3
//in second place was IE6, which takes 2 or 3 iterations roughly 5% of the time]
if(n >= 60)
{
//clear the timer
clearInterval(t);
}
}, 250);
};
domFunction(function()
{
var im=document.getElementById('webcam');
im.src=im.src+'?'+Math.random();
}, {id:'webcam'});
</script>
</head>
<body>
<img id="webcam" name="webcam" src="webcam.jpg" width="320" height="240" border="0">
</body>
</html>