document.getElementById("teste").src.clear;
document.getElementById("teste").src = "http://192.168.0.77:8080/cgi-bin/snapshot.cgi?channel=1&user=admin&pwd=minhaSenha";
var iframe = $("#teste").val();
$.ajax({
url: 'tes.php',
dataType: 'text',
data:{
foto: iframe
},
type: 'GET',
success: function(data){
alert(data);
}
});
<form id="myForm" action="teste.php">
<div id="winTelaFoto" name="winTelaFoto">
<div id='telaFoto' name="telaFoto">
<iframe id="teste" width="500" height="400" src="http://192.168.0.77:8080/cgi-bin/snapshot.cgi?channel=1&user=admin&pwd=minhaSenha"></iframe>
</div>
</div>
</form>