Hola, no he conseguido que funcione, pero he modificado algunas cosas
Te lo dejo aqui como quedo
Código HTML:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> Codigo </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
</HEAD>
<BODY>
<script language='JavaScript'>
function getImgSize(imgSrc)
{
var picture = new Image();
picture.onload = imgSrc;
picture.src = imgSrc;
document.getElementById('Debug').value = "Ruta: "+picture.src+"; Ancho: "+ picture.width+"; Ancho: "+picture.height
return false;
}
</script>
<form method="post" enctype="multipart/form-data">
<input type="file" id='demoImg' name="demoImg" size="80"><br>
<button onclick="getImgSize(document.getElementById('demoImg').value);">Codigo</button>
<input type="text" id="total" size="100" readonly><br>
Debug <input type="text" id="Debug" size="100" readonly>
</form>
</BODY>
</HTML>