how to get that prompt return string or number ?

<span class="code-keyword">var</span> ask= prompt(<span class="code-string">"</span><span class="code-string">Please insert number or string);
alert(typeof ask);
</span>

i am using above code but it return me only string not number (if i type Number).

what to do if i use below logic then this will also fail becuase now it will return only number

dialog boxes in JavaScript always return string. Use isNaN() to determine, like this:

<span class="code-keyword">var</span> ask= prompt(<span class="code-string">"</span><span class="code-string">Please insert number or string"</span>);
<span class="code-keyword">if</span> (isNaN(ask)){
    alert(<span class="code-string">"</span><span class="code-string">You enter a string"</span>);
} <span class="code-keyword">else</span> {
    alert(<span class="code-string">"</span><span class="code-string">You enter a Number"</span>);
}