Find input value from another php file

The window.parent is not necessary, because window.parent will search the page above, as the script is already running on the page above so it is irrelevant, just get the <iframe> .

To not conflict with global variables (in the scope of window. ) it would be more interesting to use jQuery itself, in the jQuery selector you can change the context, using .contentWindow , like this:

 $("<seletor>", <janela>.contentWindow.document);

  

Note: <seletor> and <janela> are examples and not code

Another problem is that you on the above page are using fotofundo and not foto , so change this:

$('#foto').val(valor);

For this reason:

$('#fotofundo').val(valor);

The whole code should look like this:

<iframe width="600" name="frmfoto" height="300" frameborder="0" src="teste2.php"></iframe>

<script>
function txfoto() {
     //Pega o iframe
     var frmfoto = $("iframe[name=frmfoto]");

     //Pega o input dentro do iframe
     var input = $("#foto", frmfoto.get(0).contentWindow.document);

     //Passa o valor do input do iframe para o input na janala principal
     $('#fotofundo').val( input.val() );
}
</script>

<!-- FOTO 1 -->
<div class="form-group">
    <label class="col-md-2 control-label" for="fotofundo">* Foto 01</label>  
       <div class="col-md-5">
           <input id="fotofundo" name="fotofundo" type="text" placeholder="" class="form-control input-md" onClick="txfoto()" />
       </div>
</div>

There are two problems in the code:

One is here:

window.parent.frmfoto.document.getElementById('foto').value;

To get the value of an element in parent-document , you should use window.parent.document :

window.parent.document.getElementById('foto').value;

The other is here:

$('#foto').val(valor);

In this id #foto is non-existent. The correct would be to get id #fotofundo using pure JavaScript (this prevents you from loading jQuery into the frame just to do this):

document.getElementById('fotofundo').value = valor;