title: asking question about using curl_setopt($ch, CURLOPT_POSTFIELDS, $postData);
body: <p>I studied yahoo app login page by curls that user can check his/her user and pass</p>
  
  <p>in this line:</p>
  
  <pre><code>$postData = "login=$login&amp;passwd=$password&amp;.src=&amp;.tries=5&amp;.bypass=
  &amp;.partner=&amp;.md5=&amp;.hash=&amp;.intl=us&amp;.tries=1&amp;.challenge=ydKtXwwZarNeRMeAufKa56.oJqaO
  &amp;.u=dmvmk8p231bpr&amp;.yplus=&amp;.emailCode=&amp;pkg=&amp;stepid=
  &amp;.ev=&amp;hasMsgr=0&amp;.v=0&amp;.chkP=N&amp;.last=&amp;.done=" . $serviceUrl; 
  </code></pre>
  
  <p>by using curl can some one explain these ampersand and dots? why they are used here?
  I know about hashing and MD5 but I don't know about these dots and.... </p>
  
  <pre><code>curl_setopt($ch, CURLOPT_POSTFIELDS, $postData); 
  </code></pre>