javascript - 可以输入限制为html?</h1> <div id="body"><blockquote> <p><strong>Possible Duplicate:</strong><br> <a href="https://stackoverflow.com/questions/451491/what-is-the-best-way-to-emulate-an-html-input-maxlengt</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="2012-09-24T16:05:53.523">2012-09-24T16:05:53.523</time> </div> <div class="flex--item ws-nowrap mb8" title="Viewed 6 times"> <span class="fc-light mr2"></span> 1024 次 </div> </div> <div id="mainbar" role="main" aria-label="question and answers"> <div class="question" 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js-gps-track" title="show questions tagged 'html'" rel="tag">html</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=""> 3 回答 <span style="display:none;" itemprop="answerCount">3</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="3"> 3 </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>这是 HTML5 的解决方案，IE9 或更早版本不支持（根据<a href="http://wufoo.com/html5/attributes/03-maxlength.html" rel="nofollow">this</a>）：</p> <pre><code><textarea maxlength="255"></textarea> </code></pre> <p>由于您可能无法放弃对 IE9（甚至可能是 IE8）的支持，因此建议您将其与 JavaScript 结合使用，以防止 textarea 上的<code>keydown</code>和<code>paste</code>事件的默认行为，正如 standup75 所建议的那样。</p> <p>以下是使用纯 JavaScript 的方法：</p> <pre><code><textarea id="txtarea" maxlength="255"></textarea> <script> var field = document.getElementById('txtarea'); if(field.addEventListener) { field.addEventListener('keydown', enforceMaxlength); field.addEventListener('paste', enforceMaxlength); } else { // IE6-8 field.attachEvent('onkeydown', enforceMaxlength); field.attachEvent('onpaste', enforceMaxlength); } function enforceMaxlength(evt) { var maxLength = 255; if(this.value.length >= maxLength) { evt.preventDefault() } } </script> </code></pre> <p><a href="http://jsfiddle.net/snJwn/" rel="nofollow">http://jsfiddle.net/snJwn/</a></p> </div> <div class="mt24"> <div class="user-action-time" style="color:#999;text-align:right;">于 2012-09-24T16:09:02.260 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="2"> 2 </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>HTML5 提供了 maxLength 属性。否则，你需要一些 javascript，在 jQuery 中，你会做类似的事情</p> <pre><code>maxLength = 50; $("textarea").on("keydown paste", function(e){ if ($(this).val().length>=maxLength) e.preventDefault(); }); </code></pre> </div> <div class="mt24"> <div class="user-action-time" style="color:#999;text-align:right;">于 2012-09-24T16:10:17.857 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="2"> 2 </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>您可以使用<code>maxlength="255"</code>（它指定元素中允许的最大字符数。）</p> <p>或者你也可以通过 jquery来完成<a href="http://www.yelotofu.com/2009/12/jquery-textarea-max-length/" rel="nofollow">这里</a>我找到了教程</p> <p>html</p> <pre><code><textarea cols="30" rows="5" maxlength="10"></textarea> </code></pre> <p>jQuery</p> <pre><code>jQuery(function($) { // ignore these keys var ignore = [8,9,13,33,34,35,36,37,38,39,40,46]; // use keypress instead of keydown as that's the only // place keystrokes could be canceled in Opera var eventName = 'keypress'; // handle textareas with maxlength attribute $('textarea[maxlength]') // this is where the magic happens .live(eventName, function(event) { var self = $(this), maxlength = self.attr('maxlength'), code = $.data(this, 'keycode'); // check if maxlength has a value. // The value must be greater than 0 if (maxlength && maxlength > 0) { // continue with this keystroke if maxlength // not reached or one of the ignored keys were pressed. return ( self.val().length < maxlength || $.inArray(code, ignore) !== -1 ); } }) // store keyCode from keydown event for later use .live('keydown', function(event) { $.data(this, 'keycode', event.keyCode || event.which); }); }); </code></pre> <p><a href="http://yelotofu.com/labs/jquery/snippets/textarea/" rel="nofollow">活生生的例子</a></p> </div> <div class="mt24"> <div class="user-action-time" style="color:#999;text-align:right;">于 2012-09-24T16:14:39.993 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/15649836" title="Question score (upvotes - downvotes)"> <div class="answer-votes large">0</div> </a> <a href="/questions/15649836" class="question-hyperlink">javascript - 画布翻转图像并与其他更改</a> </div><div class="spacer"> <a href="/questions/15649839" title="Question score (upvotes - downvotes)"> <div class="answer-votes large">1</div> </a> <a href="/questions/15649839" class="question-hyperlink">clojure - 简单 clojure 程序后的 NullPointerException</a> </div><div class="spacer"> <a href="/questions/15649841" title="Question score (upvotes - downvotes)"> <div class="answer-votes large">1</div> </a> <a href="/questions/15649841" 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