function ajaxFileUpload(upload_field)
{
// Checking file type
var re_text = /\.jpg|\.gif|\.jpeg/i;
var filename = upload_field.value;
if (filename.search(re_text) == -1) {
alert("File should be either jpg or gif or jpeg");
upload_field.form.reset();
return false;
}
document.getElementById('picture_preview').innerHTML = '<div><img src="images/progressbar.gif" border="0" /></div>';
upload_field.form.action = 'upload-picture.php';
upload_field.form.target = 'upload_iframe';
upload_field.form.submit();
upload_field.form.action = '';
upload_field.form.target = '';
return true;
}