tring">'hello'</span> <span class="token comment">// string</span>
<span class="token keyword">typeof</span> s1 <span class="token comment">// object</span>
<span class="token keyword">typeof</span> s2 <span class="token comment">// object</span>
s1 <span class="token operator">===</span> s2 <span class="token comment">// false</span>
s1 <span class="token operator">==</span> s2 <span class="token comment">// false</span>
</code></pre></div><h4 id="扩展"><a href="#扩展" class="header-anchor">#</a> 扩�