title: jQuery ajax error when data fetching
body: <p>I am using bootstrap 3.2.0 and jQuery. I can't get fetch data via jQuery and PhP</p>
  
  <pre><code>function postolayi(){
    $.ajax({
      type:'POST',
      url:'giriskontrol.php',
      data:$('#girisForm').serialize(),
      success:function(cevap){
        $("#uyari").html(cevap) 
      }
    })
  }
  </code></pre>
  
  <p>index.php</p>
  
  <pre><code>&lt;form class="form-signin" method="POST" id="girisForm"&gt;
    &lt;input  id="isim" name="isim" type="text" class="form-control" placeholder="isim" required autofocus&gt;
    &lt;input name="sifre" type="password" class="form-control" placeholder="şifre" id="sifre" required&gt;
    &lt;button class="btn btn-lg btn-primary btn-block" type="submit" onclick="postolayi();"&gt;
    Giriş Yap&lt;/button&gt;
  &lt;/form&gt;
  &lt;div class="alert alert-warning" id="uyari"&gt;&lt;/div&gt;
  </code></pre>
  
  <p>giriskontrol.php</p>
  
  <pre><code>&lt;?php
  $POST["isim"] = $isim;
  echo $isim;
  ?&gt;
  </code></pre>
  
  <p>I can't fetch data. Please somebody help.</p>
  
  <p>I changed as </p>
  
  <pre><code>&lt;?php
  $isim = $POST["isim"];
  echo $isim;
  ?&gt;
  </code></pre>
  
  <p>But still not working.</p>