 permission window. It's a good idea to safeguard your code for the case when web3 is not presented. One example of how to request these permissions safely would be:</p>
<pre class="prettyprint source lang-javascript"><code>// init metamask
try {
  if (web3 && web3.currentProvider && web3.currentProvider.isMetaMask) {
    // TODO: move this to deveryjs
    web3.currentProvider.enable();
  }
} 
catch(e) {
    // Handle exceptions here
}

</code></pre>
<p>If you don't do this you will not be able to interact 