获取光标位置

原文：https://blog.csdn.net/mafan121/article/details/78519348

html

<iframe id="editor"  width="600px" height="400px" style="border:solid 1px;"></iframe>
<input type="txt" onclick="alert(getPosition(event.target))"/>

    //初始化编辑器
    function init() {
        var ifr = document.getElementById("editor");
        var doc = ifr.contentDocument || ifr.contentWindow.document; // W3C || IE
        doc.open();
        doc.designMode="on";
        doc.contentEditable = true;
        doc.write('<html><head><style>body{margin:3px; word-wrap:break-word; word-break: break-all; }</style></head><body>GoodNessEditor</body></html>');
        doc.close();
        console.log(doc.body.innerHTML);
        doc.addEventListener('click',function(e){
            alert(getDivPosition(e));
        });
    }
    init();
    //可编辑div获取坐标
    var getDivPosition = function (event) {
        var element = event.target ?  event.target : event;
        var caretOffset = 0;
        var doc = element.ownerDocument || element.document;
        var win = doc.defaultView || doc.parentWindow;
        var sel;
        if (typeof win.getSelection != "undefined") {//谷歌、火狐
            sel = win.getSelection();
            if (sel.rangeCount > 0) {//选中的区域
                var range = win.getSelection().getRangeAt(0);
                var preCaretRange = range.cloneRange();//克隆一个选中区域
                preCaretRange.selectNodeContents(element);//设置选中区域的节点内容为当前节点
                preCaretRange.setEnd(range.endContainer, range.endOffset);  //重置选中区域的结束位置
                caretOffset = preCaretRange.toString().length;
            }
        } else if ((sel = doc.selection) && sel.type != "Control") {//IE
            var textRange = sel.createRange();
            var preCaretTextRange = doc.body.createTextRange();
            preCaretTextRange.moveToElementText(element);
            preCaretTextRange.setEndPoint("EndToEnd", textRange);
            caretOffset = preCaretTextRange.text.length;
        }
        return caretOffset;
    }
    //输入框获取光标
    var getPosition = function (event) {
        var element = event.target ?  event.target : event;
        let 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;
    }