這段代碼是從網(wǎng)上摘的，但是好像輸入框失去焦點(diǎn)就會出問題，不用iframe的話怎么解決，請大神指點(diǎn)

//鎖定編輯器中鼠標(biāo)光標(biāo)位置。。
    var _insertimg = function(str) {
        var selection = window.getSelection ? window.getSelection() : document.selection;

        var range = selection.createRange ? selection.createRange() : selection.getRangeAt(0);

        if (!window.getSelection) {

            document.getElementById('sendInput').focus();

            var selection = window.getSelection ? window.getSelection() : document.selection;

            var range = selection.createRange ? selection.createRange() : selection.getRangeAt(0);

            range.pasteHTML(str);

            range.collapse(false);

            range.select();

        } else {

            document.getElementById('sendInput').focus();

            range.collapse(false);

            var hasR = range.createContextualFragment(str);

            var hasR_lastChild = hasR.lastChild;

            while (hasR_lastChild && hasR_lastChild.nodeName.toLowerCase() == "br" && hasR_lastChild.previousSibling && hasR_lastChild.previousSibling.nodeName.toLowerCase() == "br") {

                var e = hasR_lastChild;

                hasR_lastChild = hasR_lastChild.previousSibling;

                hasR.removeChild(e)

            }

            range.insertNode(hasR);

            if (hasR_lastChild) {

                range.setEndAfter(hasR_lastChild);

                range.setStartAfter(hasR_lastChild)

            }

            selection.removeAllRanges();

            selection.addRange(range)

        }
    }