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What is whitespace? The impact of whitespace characters on HTML structure

零下一度Original: 2017-07-17 16:19:123112browse

What is a whitespace character?

White space characters: spaces, tabs, newline characters

Note: When parsing HTML, the browser will combine all whitespace characters into one space

White space characters for HTML Impact of structure

The tag placeholder in HTML5 cannot be displayed correctly</h3> <p> Poor structure causes unexpected results:</p> <p>The tag is wrapped:</p> <div class="cnblogs_code"><pre class="brush:php;toolbar:false"><span style="color: #008080">1</span> <span style="color: #008000"></span><span style="color: #008080">2</span> <span style="color: #0000ff"><</span><span style="color: #800000">textarea </span><span style="color: #ff0000">id</span><span style="color: #0000ff">="description"</span><span style="color: #ff0000"> name</span><span style="color: #0000ff">="description"</span><span style="color: #ff0000"> rows</span><span style="color: #0000ff">="5"</span><span style="color: #ff0000"> cols</span><span style="color: #0000ff">="30"</span><span style="color: #ff0000"> wrap</span><span style="color: #0000ff">="physical"</span><span style="color: #ff0000"> placeholder</span><span style="color: #0000ff">="这是一个多行输入框，输入您的个人描述"</span><span style="color: #0000ff">><br></</span><span style="color: #800000">textarea</span><span style="color: #0000ff">></span></pre></div> <p> There are spaces between tags: </p> <div class="cnblogs_code"><pre class="brush:php;toolbar:false">1 2 <textarea id="description" name="description" rows="5" cols="30" wrap="physical" placeholder="这是一个多行输入框，输入您的个人描述"> </textarea></pre></div> <p> Result: blank</p> <p><img src="https://img.php.cn/upload/article/000/000/001/fdc4b534d782ee2821b0b6513741723d-0.png" alt=""></p> <p></p> ## Reason: Because the form area contains whitespace characters (spaces, tabs, newline characters), the whitespace characters in the textarea are considered content, preventing the display of placeholder text. <p></p> Correct operation: <p></p> <pre class="brush:php;toolbar:false">1 2 <textarea id="description" name="description" rows="5" cols="30" wrap="physical" placeholder="这是一个多行输入框，输入您的个人描述"></textarea></pre> <div class="cnblogs_code"></div> Result: Space occupied! ! ! <p></p> <p><img src="https://img.php.cn/upload/article/000/000/001/fdc4b534d782ee2821b0b6513741723d-1.png" alt=""></p>Default whitespace spacing of inline-block<h3></h3>By default, there is approximately "4px" spacing between inline-block elements (different browsers will Available in different sizes). <p></p> <pre class="brush:php;toolbar:false">1 <ul>2 <li>item1</li>3 <li>item2</li>4 <li>item3</li>5 <li>item4</li>6 <li>item5</li>7 </ul></pre> <div class="cnblogs_code"></div> <pre class="brush:php;toolbar:false"> 1 { 2 margin: 0; 3 padding: 0; 4 } 5 ul { 6 list-style: none outside none; 7 padding: 10px; 8 background: green; 9 text-align: center;10 }11 ul li {12 display: inline-block;13 display: inline;14 zoom: 1;15 background: orange;16 padding: 5px;17 }</pre> <div class="cnblogs_code"></div> <p><img src="https://img.php.cn/upload/article/000/000/001/fdc4b534d782ee2821b0b6513741723d-2.png" alt=""></p>Cause: Caused by whitespace characters between tags. <p></p>Solution: At this time, you can change the structure of HTML so that the end tag of the previous li is connected to the beginning of the next li, and the whitespace characters are removed. <p></p> <pre class="brush:php;toolbar:false">1 <ul>2 <li>item1</li3 ><li>item2</li4 ><li>item3</li5 ><li>item4</li6 ><li>item5</li>7 </ul></pre> <div class="cnblogs_code"></div> <p><img src="https://img.php.cn/upload/article/000/000/001/fdc4b534d782ee2821b0b6513741723d-3.png" alt=""></p>You can click here to try the demo<p></p>Of course, whitespace characters are also characters, and they can also be removed through CSS styles Letter-spacing, word-spacing to set. For details, see: How to solve the white space spacing of inline-block elements<p></p> <p></p>White space characters that exist in the text<h2></h2>such as the following line breaks, and spaces. <p></p> <pre class="brush:php;toolbar:false"><span style="color: #0000ff"><</span><span style="color: #800000">div</span><span style="color: #0000ff">></span><span style="color: #000000">They can stay 72-hours within the Shandong province after they have entered China via the Qingdao International Airport.</span><span style="color: #0000ff"></</span><span style="color: #800000">div</span><span style="color: #0000ff">><br></span></pre> <div class="cnblogs_code"><pre class="brush:php;toolbar:false">结果：浏览器解析的时候只保留单词之间的空白符被合并为一个空格。 They can stay 72-hours within the Shandong province after they have entered China via the Qingdao International Airport.</pre></div>You can process whitespace characters in the text through the CSS attribute white-space<h3></h3>white-space: normal | pre | nowrap | pre-wrap | pre -line | inherit<p></p> <pre class="brush:php;toolbar:false">normal: 合并空白符，允许自动换行 nowrap: 合并空白符，不允许自动换行 pre-line: 合并空白符(不包括换行符)，允许自动换行 pre: 不合并空白符，不允许自动换行 pre-wrap: 不合并空白符，允许自动换行(在pre基础上，保留自动换行)</pre> <div class="cnblogs_code"></div>For details, please see: demo<p></p>Supplement<p>Supplementary<span style="font-size: 14px">Point: CSS3 has added two new line wrapping properties, word-wrap and word-break. </span></p><p>The above is the detailed content of What is whitespace? 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