Button click not duplicate?
<p>I've created the css html on my calculator. I am having a problem writing js code for point button. I do not want to write anymore, after clicking the button once. What should I do? How to write function? here is the sample code:</p>

<pre><code>&lt;html&gt;

&lt;head&gt;

&lt;title&gt;&lt;/title&gt;
&lt;script language="javascript"&gt;

function nok(){  


    value = document.getElementById("rakamkutusu").value + '.';


    document.getElementById("rakamkutusu").value = value;


}

&lt;/script&gt;
&lt;/head&gt;

&lt;body&gt;
&lt;tr&gt;
    &lt;input type='Text' class="deneme" id="rakamkutusu" name="rakam" size="70" value='0'&gt;&lt;/th&gt;
&lt;/tr&gt;
&lt;tr&gt;
   &lt;th&gt;&lt;input name="btnNOKTA" type="Button" class="butonlar"id="nokta" value=" . " onclick="nok()"&gt;&lt;/th&gt;
&lt;/tr&gt;
&lt;/body&gt;

&lt;/html&gt;
</code></pre>
