title: phone number validation in magento 1.9.2
body: <p>i have add class "validate-phoneStrict" with phone number input but still i am able to add alphabets in phone number field.
  what i have to do  to solve problem? </p>
  
  <pre><code> &lt;input type="text" name="billing[telephone]" 
   value="&lt;?php echo $this-&gt;escapeHtml($this-&gt;getAddress()-&gt;getTelephone()) ?&gt;"  title="&lt;?php echo $this-&gt;__('Telephone') ?&gt;" class="input-text validate-phoneStrict &lt;?php echo $this-&gt;helper('customer/address')-&gt;getAttributeValidationClass('telephone')  ?&gt; " 
   id="billing:telephone" /&gt;
  </code></pre>