title: on html keyup i want to call a php page and get the variable value from there and add it to an HTML content
body: <p>I know its super basic and probably simple as well, but i'm really stuck.
  just trying to get data from php in an event of onkeyup, and post it into the HTML page.</p>
  
  <p>this is my HTML</p>
  
  <pre><code>&lt;input id="dell" type="text" onkeyup="dell_function()"&lt;br&gt;
  
  &lt;p id="gimr"&gt;get her the php variable var.&lt;/p&gt;
  </code></pre>
  
  <p>php file:</p>
  
  <pre><code>&lt;?
  $var=11;
  echo $var;
  ?&gt;
  </code></pre>
  
  <p>Now i need to write the dell_function() which i want to open the php file and get the $var value, and post it as a string in here:</p>
  
  <pre><code>&lt;p id="gimr"&gt;get her the php variable var.&lt;/p&gt;
  </code></pre>
  
  <p>i know there is ajax involved but i really tried but couldn't figure it out, so how do i write the dell_function?</p>