Unexpected Exception: TypeError: window.document.getElementById(...) is null.

[fpa...@gmail.com]

HI all,

I'm trying to grab an element using its ID by issuing a javascript command in Selenium IDE:

                   javascript{document.getElementById('btnsWishAddBuy').getElementsByClassName('buy-button')[0].dataset.id}

However, even though the ID i'm trying to find matches a correct ID
(when I view the page source), the command is returning null (on Selenium IDE).

Command work both in Firefox and Chrome.

Kann anyone help me?

Thanks

Code:
------------------------------

<div id="btnsWishAddBuy" class="col-xs-12">
   <button id="articleToBasket" class="btn btn-lg addWish" data-id="101010">
      <i class="pccom-icon">$</i><span>Add</span>
   </button>
   <button data-name="Asus ...." type="button" data-loading-text="Adding..." id="add-cart" class="btn btn-lg addCar btn-secondary-outline GTM-addToCart " data-id="101010" data-price="9" data-brand="Asus ..." data-category="Placas Base" data-qty="1">
      <i class="com-icon">}</i>
      <i class="com-icon arrow">yx</i>
      <span>Add to ...</span>
   </button>
   <button type="button" data-loading-text="Adding ..." class="btn btn-primary btn-lg buy GTM-addToCart buy-button" data-name="Asus Rampage" data-id="101010" data-price="9" data-brand="Asus" data-category="Base" data-qty="1">
      <strong>buy</strong>
      <i class="com-icon">]</i>
   </button>
</div>

[Akshat Gupta]

Try in this manner

http://www.guru99.com/execute-javascript-selenium-webdriver.html