javascript - 入力をhtmlに限定できますか?</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-maxl</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">質問する</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">質問する</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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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"> </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/javascript" class="post-tag js-gps-track" title="show questions tagged 'javascript'" rel="tag">javascript</a><a href="/tags/html" class="post-tag 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 に答える <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>これは HTML5 のソリューションであり、IE9 以前ではサポートされていません (これによると<a href="http://wufoo.com/html5/attributes/03-maxlength.html" rel="nofollow">)</a> :</p> <pre><code><textarea maxlength="255"></textarea> </code></pre> <p>おそらく IE9 (およびおそらく IE8) のサポートを終了することはできないため、standup75 が提案したように、テキストエリアでの<code>keydown</code>およびイベントのデフォルトの動作を防止して、それを JavaScript と組み合わせることをお勧めします。<code>paste</code></p> <p>プレーンな JavaScript でそれを行う方法は次のとおりです。</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 に答える</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>を使用できます<code>maxlength="255"</code>(要素で許可される最大文字数を指定します)。</p> <p>または、jquery <a href="http://www.yelotofu.com/2009/12/jquery-textarea-max-length/" rel="nofollow">here で</a>これを行うこともできますチュートリアルを見つけました</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">実際の例</a></p> </div> <div class="mt24"> <div class="user-action-time" style="color:#999;text-align:right;">于 2012-09-24T16:14:39.993 に答える</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 は maxLength 属性を提供します。それ以外の場合は、JavaScript が必要です。jQuery では、次のようにします。</p> <pre><code>maxLength = 50; $("textarea").on("keydown paste", function(e){ if ($(this).val().length>=maxLength) e.preventDefault(); 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