Why write js two output
<p>i need to help , whey the code get the output : first "underfind" and second "i'm local"
Why it's the problem? and my second question is what the name of this problem. </p>

<p><strong>what is called problemert in js languages? concepts?</strong></p>

<p>enter code here</p>

<pre><code>    &lt;script type="text/javascript"&gt;
        var testVar = "i'm global";
        function example( ) {
            alert(testVar); 
            var testVar = "i'm local";
            alert(testVar);   

         }
             example();     
    &lt;/script&gt;
</code></pre>
