title: Protractor : Remove special characters from String
body: <p>I'm writing protractor tests for my angular application. 
  Here is one of my test case. 
  I want to compare a span value before and after a button click.</p>
  
  <pre><code>it('Compare the dollar values', function () {
              var a = mypage.a.getText();
              mypage.clickBtnUS();
              expect(toNumber(mypage.a.getText())).toEqual(a * 
                mypage.fxRate.getText());
      });
  </code></pre>
  
  <p><em>mypage.a</em> is a span which display dollar amount in format - <strong><em>$ 643,584</em></strong>. I wants to <strong><em>remove the special characters such as $ and , from this string before numeric conversion</em></strong>. Without removing $ and , will result in producing NaN after numeric conversion.
  How can I do that. </p>
  
  <p>Any help is really appreciated. 
  Thanks in advance. </p>