title: remove attribute by using getelementbyclass
body: <p>Here i am trying to call class and get the value in variable to remove its attribute <strong>style</strong> and setting <strong>style</strong> again but it shows error like this </p>
  
  <blockquote>
    <p>Uncaught TypeError: cls.removeAttribute is not a function.</p>
  </blockquote>
  
  <pre><code>cls = document.getElementsByClassName("ps-scrollbar-x-rail");
  cls1 = document.getElementsByClassName("ps-scrollbar-x");
  cls2 = document.getElementsByClassName("ps-scrollbar-y-rail");
  //alert(cls);
  //alert(cls1);
  //alert(cls2);
  //console.log(cls);
  //console.log(cls1);
  //console.log(cls2);
  
  cls.removeAttribute("style"); 
  cls1.removeAttribute("style");
  cls2.removeAttribute("style");
  
  cls.setAttribute("style","width: 600px; left: 258px; bottom: 1px;"); 
  cls1.setAttribute("style","left: 143px; width: 333px;");
  cls2.setAttribute("style","top: 0px; right: -255px;");
  </code></pre>
  
  <p>Onclick to call this method. Which shows error.</p>