Question

我正在为crossbrowser input＆amp; textarea selection getter和setter编写扩展。这就是我编写代码的方式：

HTMLInputElement.prototype.getSelectionRange = get_selection_range;
HTMLInputElement.prototype.setSelection = set_selection_range;
HTMLTextAreaElement.prototype.getSelectionRange = get_selection_range;
HTMLTextAreaElement.prototype.setSelection = set_selection_range;

get_selection_range和set_selection_range是那些扩展函数。所以我只想替换

someInputElement.selectionStart = a;  // and whole lot of code due to browser
someInputElement.selectionEnd = b;    // compatibility

只是

someInputElement.setSelection(a, b);
someInputElement.setSelection({ start: a, end: b });
someOtherElement.setSelection(someInputElement.getSelection());

但后来我在IE7中遇到了几个困难。首先，IE7不知道什么是HTMLInputElement。

我不想扩展整个Object。好吧，那将是我要做的最后一件事，但我想逃避它。函数get_selection_range和set_selection_range都没关系，不要问内在的是什么，你已经看过几次了。

所以问题是：JS7中的HTMLInputElement是否有任何合法替代？

UPD：我已经制定了自己的解决方案而没有扩展任何全局对象类型：

var SmartInputSelection = Base.extend({
    constructor: function (options) {
        this.node = options.node;
        this.CHARACTER = "character";
        this.END_TO_END = "EndToEnd";
        this.END_TO_START = "EndToStart";
    },
    setSelection: function (a, b) {
        if (b === undefined && typeof a == "number")
            b = a;
        else if (b === undefined) {
            b = a.end;
            a = a.start;
        }

        if (this.node.selectionStart !== undefined) {
            this.node.selectionStart = a;
            this.node.selectionEnd = b;
        } else {
            var textRange = this.node.createTextRange();
            textRange.collapse(true);
            textRange.moveStart(this.CHARACTER, a);
            textRange.moveEnd(this.CHARACTER, b - a);
            textRange.select();
        }
    },
    getSelection: function () {
        var start, end;
        if (this.node.selectionStart !== undefined) {
            start = this.node.selectionStart;
            end = this.node.selectionEnd;
        } else {
            var range = document.selection.createRange();
            if (range == null) {
                start = end = 0;
            }

            var textRange = this.node.createTextRange(),
            duplicate = textRange.duplicate();
            textRange.moveToBookmark(range.getBookmark());
            duplicate.setEndPoint(this.END_TO_END, textRange);
            end = duplicate.text.length;
            duplicate.setEndPoint(this.END_TO_START, textRange);
            start = duplicate.text.length;
        }

        return {
            start: start,
            end: end
        };
    }
});

所以现在我只需声明：

function SelectSomeTextInsideInput (input /* input is some DOM element */) {
    var smartInputSelection = new SmartInputSelection({ node: input });
    smartInputSelection.setSelection(0);
    smartInputSelection.setSelection(2, 5);
    smartInputSelection.setSelection({ start: 2, end: 5 });
    smartInputSelection.getSelection(); // start: 2, end: 5
}

Answer 1

没有。我最近和IE9打架，然后通过切换到HTML5模式让它工作我猜IE7太老了，不能以任何方式支持它。

无论如何，尝试将此声明放在页面顶部：

<!doctype HTML>

编辑：并在此处查看此答案：Element.prototype in IE7?

Answer 2

您不应该依赖这些对象进行全局定义，因为您已经注意到在某些浏览器中它们不是。

IE7中的HTMLInputElement

2 个答案: