youtube 以iframe嵌入網頁符合自適應RWD

 網頁版面為

<span class="pln">
</span><span class="tag">&lt;div</span><span class="pln"> </span><span class="atn">class</span><span class="pun">=</span><span class="atv">"videoWrapper"</span><span class="tag">&gt;</span><span class="pln">
</span><span class="tag">&lt;iframe</span><span class="pln"> </span><span class="atn">allow</span><span class="pun">=</span><span class="atv">"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture"</span><span class="pln"> </span><span class="atn">allowfullscreen</span><span class="pun">=</span><span class="atv">""</span><span class="pln"> </span><span class="atn">frameborder</span><span class="pun">=</span><span class="atv">"0"</span><span class="pln"> </span><span class="atn">height</span><span class="pun">=</span><span class="atv">"315"</span><span class="pln"> </span><span class="atn">src</span><span class="pun">=</span><span class="atv">"https://www.youtube.com/embed/影片ID"</span><span class="pln"> </span><span class="atn">title</span><span class="pun">=</span><span class="atv">"YouTube video player"</span><span class="pln"> </span><span class="atn">width</span><span class="pun">=</span><span class="atv">"560"</span><span class="tag">&gt;&lt;/iframe&gt;</span><span class="pln">
</span><span class="tag">&lt;/div&gt;</span><span class="pln">
</span>

CSS樣式

.videoWrapper{
	position: relative; 
	padding-bottom: 56.25%; 
	height: 0; 
	overflow: hidden; 
	max-width: 100%; 
}

.videoWrapper iframe{
	position: absolute; 
	top: 0; 
	left: 0; 
	width: 100%; 
	height: 100%;
}

參考：
16:9的比例為 56.25%
4:3的比例為 75%

相關：
RWD:以區塊對角線的比例來設定隨螢幕大小自動伸縮的背景圖

如何檢查 mysqli_query() insert,update是否成功

要檢查 mysqli_query() 插入是否成功，可以使用 mysqli_affected_rows() 函數。 此函數返回受查詢影響的行數。 如果插入成功，受影響的行數應該大於 0。如下：

$result = mysqli_query($conn, $query);
if (mysqli_affected_rows($conn) > 0) {
    // insert was successful
} else {
    // insert failed
}

此方法僅適用於insert, update跟delete 的queries查詢。 對於select資料，mysqli_affected_rows() 將始終返回 0。 在這種情況下，可以使用 mysqli_num_rows() 檢查select查詢是否返回任何行。

$result = mysqli_query($conn, $query);
if (mysqli_num_rows($result) > 0) {
    // query returned one or more rows
} else {
    // query returned no rows
}