javascript获取选中文字-兼容各浏览器

function getSelectedText() {
                if (window.getSelection) {
                    // This technique is the most likely to be standardized.
                    // getSelection() returns a Selection object, which we do not document.
                    return window.getSelection().toString();
                }
                else if (document.getSelection) {
                    // This is an older, simpler technique that returns a string
                    return document.getSelection();
                }
                else if (document.selection) {
                    // This is the IE-specific technique.
                    // We do not document the IE selection property or TextRange objects.
                    return document.selection.createRange().text;
                }
            }