Disabling the textbox not working
<p><em>I am writing small form, so jQuery is out of game here.</em></p>

<p>Question is, why this code don't want to work?</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>function isChecked() {
  if (document.getElementById("priceCall").checked) {
    document.getElementById("mailingPrice").setAttribute("disabled", false);
  } else {
    document.getElementById("mailingPrice").setAttribute("disabled", true);
  }
}

var priceCall = document.getElementById("priceCall");
priceCall.addEeventListener("change", isChecked);</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;h2&gt;Costs of sending? (point if yes)&lt;/h2&gt;
Mailing price:
&lt;input id="mailingPrice" type="text" disabled&gt;
&lt;input type="checkbox" id="priceCall" onchange="isChecked()"&gt;
&lt;br&gt;
&lt;br&gt;</code></pre>
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</div>
</p>