how to allow only alphabets in input box with angular js
<p>I have a input box with angular js validation.. The code is </p>

<pre><code>    &lt;div class="col-sm-12"&gt;
        &lt;input type="text" name="drug_name" class="form-control" placeholder="Drug name" ng-pattern="/[aA-zZ\s]$/" ng-model="vmp.medication.drug_name" maxlength="150" typeahead="drugn as drugn.drugName for drugn in vmp.drugList | filter:$viewValue" autocomplete="off"  required&gt;
&lt;span class="pull-right font-10"&gt;(Max 150 chars.)&lt;/span&gt;
  &lt;span ng-messages="form.drug_name.$dirty &amp;&amp; form.drug_name.$error"&gt;
   &lt;span ng-message="required" class="error-inner"&gt;Drug name is required.&lt;/span&gt;
   &lt;span ng-message="pattern" class="error-icn"&gt;Only Alphabets are allowed&lt;/span&gt; &lt;/span&gt;
     &lt;/div&gt;
</code></pre>

<p>The above code is validating the textbox and throwing error if I enter numbers. But What I need is , It should restrict entering numbers. The user should not be able to enter numbers in the textbox at all.. Can anyone helpme to do this..</p>