ruby-on-rails - 如何隐藏 if the embedded video url is blank in rails app ?</a></h1> <div class="ml12 aside-cta flex--item print:d-none sm:ml0 sm:mb12 sm:order-first sm:as-end"> <a href="https://stackoverflow.com/questions/ask" target="_blank" class="ws-nowrap s-btn s-btnprimary">问问题</a></div> </div> <div class="d-flex fw-wrap pb8 mb16 bb bc-black-075"> <div class="flex--item ws-nowrap mr16 mb8"> <span class="fc-light mr2"></span> </div> <div class="flex--item ws-nowrap mr16 mb8" title="2022-04-17 15:46:40Z"> <span class="fc-light mr2">问问题</span> <time itemprop="dateCreated" datetime="2012-06-28T16:10:06.177">2012-06-28T16:10:06.177</time> </div> <div class="flex--item ws-nowrap mb8" title="Viewed 6 times"> <span class="fc-light mr2"></span> 694 次 </div> </div> <div id="mainbar" role="main" aria-label="question and answers"> <div class="question" data-questionid="4" data-position-on-page="0" data-score="763" id="question"> <div class="post-layout"> <div class="votecell post-layout--left"> <div class="js-voting-container d-flex jc-center fd-column ai-stretch gs4 fc-black-200" data-post-id="4"> <button class="js-vote-up-btn flex--item s-btn s-btnunset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Up vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-peeufs8c"> <svg aria-hidden="true" class="svg-icon iconArrowUpLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 25h32L18 9 2 25Z"></path></svg> </button> <div id="--stacks-s-tooltip-peeufs8c" class="s-popover s-popovertooltip pe-none" aria-hidden="true" role="tooltip">This question shows research effort; it is useful and clear<div class="s-popover--arrow"></div></div> <div class="js-vote-count flex--item d-flex fd-column ai-center fc-black-500 fs-title" itemprop="upvoteCount" data-value=""> 0 </div> <button class="js-vote-down-btn flex--item s-btn s-btnunset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Down vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-04106eqn"> <svg aria-hidden="true" class="svg-icon iconArrowDownLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 11h32L18 27 2 11Z"></path></svg> </button><div id="--stacks-s-tooltip-04106eqn" class="s-popover s-popovertooltip pe-none" aria-hidden="true" role="tooltip">This question does not show any research effort; it is unclear or not useful<div class="s-popover--arrow"></div></div> <div id="--stacks-s-tooltip-tgvwendx" class="s-popover s-popovertooltip pe-none" aria-hidden="true" role="tooltip">Bookmark this question.<div class="s-popover--arrow"></div></div> <a class="js-post-issue flex--item s-btn s-btnunset c-pointer py6 mx-auto" data-shortcut="T" data-ks-title="timeline" data-controller="s-tooltip" data-s-tooltip-placement="right" aria-label="Timeline" aria-describedby="--stacks-s-tooltip-abwmy15k"><svg aria-hidden="true" class="mln2 mr0 svg-icon iconHistory" width="19" height="18" viewBox="0 0 19 18"><path d="M3 9a8 8 0 1 1 3.73 6.77L8.2 14.3A6 6 0 1 0 5 9l3.01-.01-4 4-4-4h3L3 9Zm7-4h1.01L11 9.36l3.22 2.1-.6.93L10 10V5Z"></path></svg></a><div id="--stacks-s-tooltip-abwmy15k" class="s-popover s-popovertooltip pe-none" aria-hidden="true" role="tooltip">Show activity on this post.<div class="s-popover--arrow"></div></div> </div> </div> <div class="postcell post-layout--right"> <div class="s-prose js-post-body" itemprop="text"> <p>This must be very simple. But I just can't seem to find the proper solution.</p>

<p>I have a model with an embedded video attribute. </p>

<p>I made it happen like this:</p>

<pre><code> On my show page
 <iframe width="560" height="315" src="<%= @trip.youtube %>" frameborder="0" allowfullscreen></iframe>
</code></pre>

<p>Everything works fine, but the thing is that i don't want to show this part if the youtube url is blank. Otherwise I am left with a huge white space, which I don't need.</p>

<p>I've tried to play around with <strong>unless</strong> or <strong>if</strong> conditions</p>

<pre><code> <% if @trip.youtube.blank? %>
 <iframe width="0" height="0" src="<%= @trip.youtube %>" frameborder="0" class="hidden" allowfullscreen></iframe>
 <% else %>
 <iframe width="560" height="315" src="<%= @trip.youtube %>" frameborder="0" allowfullscreen></iframe>
 <% end %>
</code></pre>

<p>But I'm doing something wrong.
 Any suggestions for a better way ? 
Thanks.</p>
 </div> <div class="mt24 mb12"> <div class="post-taglist d-flex gs4 gsy fd-column"> <div class="d-flex ps-relative fw-wrap"> <a href="/tags/ruby-on-rails" class="post-tag js-gps-track" title="show questions tagged 'ruby-on-rails'" rel="tag">ruby-on-rails</a><a href="/tags/iframe" class="post-tag js-gps-track" title="show questions tagged 'iframe'" rel="tag">iframe</a><a href="/tags/youtube" class="post-tag js-gps-track" title="show questions tagged 'youtube'" rel="tag">youtube</a><a href="/tags/show-hide" class="post-tag js-gps-track" title="show questions tagged 'show-hide'" rel="tag">show-hide</a> </div> </div> </div> </div> <span class="d-none" itemprop="commentCount">4</span> </div> </div> <div class="js-zone-container zone-container-responsive"> <div id="dfp-isb" class="everyonelovesstackoverflow everyonelovesinline-sidebar mx-auto" style="min-height: auto; height: auto; display: none;"></div> <div class="js-report-ad-button-container mx-auto" style="width: 300px"></div> </div> <div id="answers"> <a name="tab-top"></a> <div id="answers-header"> <div class="answers-subheader d-flex ai-center mb8"> <div class="flex--item fl1"> <h2 class="mb0" data-answercount=""> 2 回答 <span style="display:none;" itemprop="answerCount">2</span> </h2> </div> </div> </div> <a name="7"></a> <div id="answer-7" class="answer js-answer accepted-answer" data-answerid="7" data-parentid="4" data-score="506" data-position-on-page="1" data-highest-scored="1" data-question-has-accepted-highest-score="1" itemprop="suggestedAnswer" itemscope="" itemtype="https://schema.org/Answer"> <div class="post-layout"> <div class="votecell post-layout--left"> <div class="js-voting-container d-flex jc-center fd-column ai-stretch gs4 fc-black-200" data-post-id="7"> <button class="js-vote-up-btn flex--item s-btn s-btnunset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Up vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-dgvag2l3"> <svg aria-hidden="true" class="svg-icon iconArrowUpLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 25h32L18 9 2 25Z"></path></svg> </button><div id="--stacks-s-tooltip-dgvag2l3" class="s-popover s-popovertooltip pe-none" aria-hidden="true" role="tooltip">This answer is useful<div class="s-popover--arrow"></div></div> <div class="js-vote-count flex--item d-flex fd-column ai-center fc-black-500 fs-title" itemprop="upvoteCount" data-value="0"> 0 </div> <button class="js-vote-down-btn flex--item s-btn s-btnunset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Down vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-gn8ppsfv"> <svg aria-hidden="true" class="svg-icon iconArrowDownLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 11h32L18 27 2 11Z"></path></svg> </button> </div> </div> <div class="answercell post-layout--right"> <div class="s-prose js-post-body" itemprop="text"> <p>Why not just use:</p>

<pre><code><% if @trip.youtube.present? %>
 <iframe width="560" height="315" src="<%= @trip.youtube %>" frameborder="0" allowfullscreen></iframe>
<% end %>
</code></pre>

<p>And leave it at that?</p>
 </div> <div class="mt24"> <div class="user-action-time" style="color:#999;text-align:right;">于 2012-06-28T16:26:47.890 回答</div> </div> </div> </div> </div><a name="7"></a> <div id="answer-7" class="answer js-answer accepted-answer" data-answerid="7" data-parentid="4" data-score="506" data-position-on-page="1" data-highest-scored="1" data-question-has-accepted-highest-score="1" itemprop="suggestedAnswer" itemscope="" itemtype="https://schema.org/Answer"> <div class="post-layout"> <div class="votecell post-layout--left"> <div class="js-voting-container d-flex jc-center fd-column ai-stretch gs4 fc-black-200" data-post-id="7"> <button class="js-vote-up-btn flex--item s-btn s-btnunset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Up vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-dgvag2l3"> <svg aria-hidden="true" class="svg-icon iconArrowUpLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 25h32L18 9 2 25Z"></path></svg> </button><div id="--stacks-s-tooltip-dgvag2l3" class="s-popover s-popovertooltip pe-none" aria-hidden="true" role="tooltip">This answer is useful<div class="s-popover--arrow"></div></div> <div class="js-vote-count flex--item d-flex fd-column ai-center fc-black-500 fs-title" itemprop="upvoteCount" data-value="0"> 0 </div> <button class="js-vote-down-btn flex--item s-btn s-btn__unset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Down vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-gn8ppsfv"> <svg aria-hidden="true" class="svg-icon iconArrowDownLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 11h32L18 27 2 11Z"></path></svg> </button> </div> </div> <div class="answercell post-layout--right"> <div class="s-prose js-post-body" itemprop="text"> <p>aaa... such a dumb mistake.</p>

<p>In my _form I had:</p>

<pre><code> <div class="field">
 <%= f.label :youtube %><br />
 <%= f.text_field :youtube,:value => 'http://' %><br />
 </div>
</code></pre>

<p>Since the field had already - <strong>http://</strong>, either way, with or without youtube url, rails didn't identify it as blank :))</p>

<p>needs to be simply:</p>

<pre><code> <div class="field">
 <%= f.label :youtube %><br />
 <%= f.text_field :youtube %><br/>
 </div> 
</code></pre>

<p>and </p>

<pre><code> <% if @trip.youtube.present? %>
 <iframe width="560" height="315" src="<%= @trip.youtube %>" frameborder="0" allowfullscreen></iframe>
 <% end %>
</code></pre>

<p>Works like a charm. Thanks :) </p>
 </div> <div class="mt24"> <div class="user-action-time" style="color:#999;text-align:right;">于 2012-06-28T17:41:41.640 回答</div> </div> </div> </div> </div></div> </div> <div id="sidebar" class="show-votes" role="complementary" aria-label="sidebar"> <div class="module sidebar-related"> <h4 id="h-related">Related</h4> <div class="related js-gps-related-questions" data-tracker="rq=1"> <div class="spacer"> <a href="/questions/10219959" title="Question score (upvotes - downvotes)"> <div class="answer-votes large">1</div> </a> <a href="/questions/10219959" class="question-hyperlink">javascript - 如何从javascript错误行号获取实际行</a> </div><div class="spacer"> <a href="/questions/10219964" title="Question score (upvotes - downvotes)"> <div class="answer-votes large">2</div> </a> <a href="/questions/10219964" class="question-hyperlink">bash - 我需要编辑 bash 脚本以选择一个字母来执行单独的命令</a> </div><div class="spacer"> <a href="/questions/10219969" title="Question score (upvotes - downvotes)"> <div class="answer-votes 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