php与ajax集成

I have a record of carriers and clients. When selecting a carrier on the customer screen, I need it to be automatically filled out the carrier's e-mail and telephone. The PHP file is returning a JSON correctly, but it is dropping in the error of jquery and not in success. I checked in Firefox's Firebug and the HTML tab of the console, where the GET requisition is reset.

<?php
include "Config/config_sistema.php";
$res = mysql_query("SELECT * FROM transportadoras");
$menu_items = null;
while($ln = mysql_fetch_object($res)){
    $menu_items[] = $ln;
}
json_encode($menu_items);
?>

<script>
    $("body").on("change","#transportadoras",function(event){
        event.preventDefault();
        var trigger=$(this);
        $.ajax ({
            type: "POST",
            url: "buscaDadosTransportadora.php",
            dataType: 'json',
            success: function (data) {
                $("#telefone_transp").val(data.telefone);
                $("#email_transp").val(data.email);
            },
            error: function (data) {
                alert("Erro");
            },
        });
    });
</script>   

return in ajax

[{"ID":"5","Nome":"Vinicius","email":"viniciusbalbinot91@gmail.com","telefone":"32680018"},{"ID":"6","Nome":"teste","email":"teste@teste.com.br","telefone":"12345567"}]

You response is array .

[{"ID":"5","Nome":"Vinicius","email":"viniciusbalbinot91@gmail.com","telefone":"32680018"},....]

you should loop through data.

 success: function (data) {
    $.each(data,function(user){ /* code ...*/});           
 }

If you want some current row select one row from mysql .

hope it can help u

php.php

$inp=$_POST["data"];  
$txt[0]=array("ID"=>"5","Nome"=>"Vinicius","email"=>"viniciusbalbinot91@gmail.com","telefone"=>"32680018");
$txt[1]=array("ID"=>"6","Nome"=>"teste","email"=>"teste@teste.com.br","telefone"=>"12345567");

for($c=0;$c<sizeof($txt);$c++)
{
    if($txt[$c]["ID"]==$inp)
    {echo json_encode($txt[$c]);}   
}

index.php

ID:<input id="txt" name="txt" type="text" />
<br><br>

Name:<input id="name" name="txt0" type="text" disabled="disabled"/><br>
Email:<input id="email" name="txt0" type="text" disabled="disabled"/><br>
Tel:<input id="tel" name="txt0" type="text" disabled="disabled"/><br>

js

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script>
$("document").ready(function()
{
    $("#txt").keyup(function ()
    {
        $.ajax(
        {
            type:"POST",
            dataType:"json",
            url:"php.php",
            data:{data : $("#txt").val()}, 

            success: function(data)
            {
                $("#name").val(data.Nome);
                $("#email").val(data.email);
                $("#tel").val(data.telefone);
            },
            error: function () 
            {
                alert("Error!");
            }
        }); 


    });

});

</script>