[廾匸] 2018-02-06 09:43 采纳率: 87.5%
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如何实现textarea中输入@在右下方出现一个div

我想实现一个效果就是在textarea中输入一个@然后在该文字的右下方出现一个div，里面是放一个列表的，跟QQ的输入一样，不管是复制还是直接输入的@都出现这个功能图片说明
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  • hfhan_872914334 2018-02-07 03:22
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<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        *{padding:0;margin:0;}
        .box{position:relatuve;}
        #ipt{
            font-size:16px;
            padding-left:5px;
            height:30px;
            line-height:30px;
        }
        #list{
            position:absolute;
            list-style:none;
            width:150px;
            display:none;
        }
        #list li{height:25px;line-height:25px;}
        #list li:hover{background:#efefef;cursor:pointer;}
    </style>
</head>
<body>
    <div class='box'>
        <input type="text" id='ipt'>
        <ul id='list'>
            <li>qq.com</li><li>sina.com</li><li>163.com</li>
        </ul>
    </div>

    <script>
        var ipt = document.getElementById('ipt');   
        var list = document.getElementById('list');

        ipt.oninput = function(e){
            //console.log(e)
            //获取光标位置
            var position = getPosition(ipt);
            console.log(position,(ipt.value+'').length)
            //如果光标在文本最后面,且最后一个是@
            if((position == (ipt.value+'').length) && /@$/.test(ipt.value)){
                //把双字节的替换成两个单字节的然后再获得长度 
                var len = (ipt.value || '').replace(/[^\x00-\xff]/g,"01").length/2;
                var fz = parseFloat(window.getComputedStyle(ipt).fontSize);
                var wd = parseFloat(window.getComputedStyle(ipt).width);
                list.style.left = fz*len>wd?wd:fz*len + "px";
                list.style.display = "block";
            }else{
                list.style.display = "none";
            }
        }
        for(var i=0;i<list.children.length;i++){
            list.children[i].onclick = function(e){
                ipt.value += e.target.innerHTML;
                list.style.display = "none";
            }
        }
        //输入框获取光标
        function getPosition(element) {
            var cursorPos = 0;
            if (document.selection) {//IE
                var selectRange = document.selection.createRange();
                selectRange.moveStart('character', -element.value.length);
                cursorPos = selectRange.text.length;
            } else if (element.selectionStart || element.selectionStart == '0') {
                cursorPos = element.selectionStart;
            }
            return cursorPos;
        }
    </script>
</body>
</html>
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