javascript - 如何在打字时设置文本框格式？

Question

当用户在文本框中键入内容时，我希望它使用小数来格式化自己。

例如，如果用户输入 10000，我希望他在输入时显示为 10,000。

Answer 1

给你。处理退格键/删除键使其变得特别具有挑战性。蛮好玩的! :-)

我已将其添加到我的在线脚本组合中:rack.pub .

function toast(a,b){b||(b=2750);var c={message:a,timeout:b};snackbarContainer.MaterialSnackbar.showSnackbar(c)}var doc=document,textArea=doc.getElementById("area"),numArray=[],backArray=[],num="",numF="",regx="",thisChar="",lastChar="",str="",index=0;window.snackbarContainer=doc.querySelector("#toast"),textArea.addEventListener("keydown",function(){var a=event.keyCode;if(str=this.value,(8==a||46==a)&&(backArray=[],index=str.length-1,lastChar=str.charAt(index),!isNaN(lastChar)||","==lastChar))for(var b=str.length-1;b>=0;b--){if(" "==str.charAt(b))return;if(isNaN(str.charAt(b))&&","!=str.charAt(b))return;backArray.push(str.charAt(b))}if(32==a&&backArray[1]){var c=backArray.reverse().slice(0,-1).join(""),d=c.replace(/\,/g,""),e=Number(d).toLocaleString().toString(),f=str.lastIndexOf(c);f>=0&&f+c.length>=str.length&&(str=str.substring(0,f)+e),this.value=str}}),textArea.addEventListener("keypress",function(){if(thisChar=this.value.slice(-1),isNaN(thisChar)){num=numArray.join(""),numArray=[],numF=Number(num).toLocaleString().toString(),regx=num+"(?!.*"+num+")",regx=new RegExp(regx);var a=this.value.replace(regx,numF);this.value=a}else{if(" "==thisChar){num=numArray.join(""),numArray=[],numF=Number(num).toLocaleString().toString(),regx=num+"(?!.*"+num+")",regx=new RegExp(regx);var a=this.value.replace(regx,numF);return void(this.value=a)}numArray.push(thisChar)}});

        html body {
            font-family: 'Roboto', sans-serif;
            background: #f5f5f5;
        }
        .text-right{
            text-align:right;
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            text-align:center;
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        .text-left{
            text-align:left;
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        .thin{
            font-weight: 100;
        }
        .heading{
            font-size:3em;
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        .subtitle{
            margin-top: -16px;
        }
        #submit{
            margin-top:10px;
        }

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                    <h1 class="mdl-color-text--indigo-900 text-right thin">commas.js demo</h1>
                    <h6 class="mdl-color-text--indigo-500 text-right subtitle">
                        JavaScript to automatically add commas to numbers in a text area
                    </h6>
                </div>
                <div class="mdl-layout-spacer"></div>
            </section>
            
            <section class="mdl-grid">
                <div class="mdl-layout-spacer"></div>
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                    <h6 class="mdl-color-text--black thin">
                        Basically it auto formats numbers as you type in the text area.  Give it a try.
                    </h6>
                </div>
                <div class="mdl-layout-spacer"></div>
            </section>
            
            <section class="mdl-grid">
                <div class="mdl-layout-spacer"></div>
                <div class="mdl-textfield mdl-js-textfield mdl-cell mdl-cell--4-col">
                    <textarea class="mdl-textfield__input" type="text" rows= "3" id="area" ></textarea>
                    <label class="mdl-textfield__label" for="area">Type Here...</label>
                </div>
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            </section>
            
        </main>
    </div>
        
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