title: use of "Execute Javascript" Selenium2Library to retrieve value
body: <p>Using the below script to retrieve value by passing WebElement as argument in javascript:</p>
  
  <pre><code>${elem}=Get WebElement    name=productField
  ${value}=Execute Javascript    return document.arguments[0].value,'${elem}'; 
  Log To Console    ${value}  
  </code></pre>
  
  <p>Seeing the below error:
  WebDriverException: Message: unknown error: Cannot read property '0' of undefined</p>