Selenium:- Popup handelling in HTML - selenium

Question

I am using Firefox Quantum.
It's something different than Mozzila firefox. I can't use firebug now as it is not supporting.How can i verify that the i am on a different frame.
As currently i can't write on the popup message. Maybe it is on different frame.
Can anyone explain me with proper example.
The HTMLM of the code is:-
<div class="store_form">
<div class="row">
<div class="col s12 m12 marg-top">
<div class="row">
<div class="col s12 m6 store_band_contact">
</div>
<div class="col s12 m6 store_add_left">
</div>
</div>
</div>
<form id="form_contact" class="col s12 m12" novalidate="novalidate">
<div id="errorMsg"></div>
<!-- <div class="row">
<p class="col s12" style="font-size: 15px;" >
<strong id="buyer_company"></strong>
</p>
</div> -->
<!-- <div class="row">
<p class="col s12" id="">Subject: Request to remove my bid
</p>
</div> -->
<div class="row">
<div class="input-field col s12">
<span class="editFiledHeading">Request to remove my bid</span>
<!-- Contact Seller -->
<textarea name="comment" maxlength="20000" id="comment" class="ckeditor" placeholder="" style="visibility: hidden; display: none;"></textarea><div id="cke_comment" class="cke_1 cke cke_reset cke_chrome cke_editor_comment cke_ltr cke_browser_webkit" dir="ltr" lang="en" role="application" aria-labelledby="cke_comment_arialbl" style="width: 99.8%;"><span id="cke_comment_arialbl" class="cke_voice_label">Rich Text Editor, comment</span><div class="cke_inner cke_reset" role="presentation"><span id="cke_1_top" class="cke_top cke_reset_all" role="presentation" style="height: auto; user-select: none;"><span id="cke_12" class="cke_voice_label">Editor toolbars</span><span id="cke_1_toolbox" class="cke_toolbox" role="group" aria-labelledby="cke_12" onmousedown="return false;"></span></span><div id="cke_1_contents" class="cke_contents cke_reset" role="presentation" style="height: 200px;"><span id="cke_16" class="cke_voice_label">Press ALT 0 for help</span><iframe src="" frameborder="0" class="cke_wysiwyg_frame cke_reset" title="Rich Text Editor, comment" aria-describedby="cke_16" tabindex="0" allowtransparency="true" style="width: 439px; height: 100%;"></iframe></div></div></div>
<input type="hidden" name="bid" id="bid_id" value="1035">
</div>
</div>
<div class="row" style="margin-top: 10px;">
<div class="col s6">
<p style="margin: 5px 0 0;">
<input type="checkbox" name="is_copy" id="is_copy" value="1">
<label for="is_copy">Send me a copy</label>
</p>
</div>
<div class="col s6">
<span class="right remainingLimit" id="comment_label" data-length="2500">Remaining: 2500</span>
</div>
</div>
<div class="row">
<div class="col s12">
<p class="defaultP">
If you like to remove a bid you can do that by
sending the request to the seller. Please make
sure that you state the reason for doing this.
Obvious accidents by using the wrong value are
easy to justify.
Please note that it is up to the seller to accept
or decline your request!
</p>
</div>
</div>
<div class="row">
<div class="col s12 center" style="margin: 20px 0 15px;">
<button class="transParentBtnSmall">Submit</button>
</div>
</div>
</form>
</div>
</div>