以下内容将告诉您是否在所有主流浏览器的文本输入中选择了所有文本。

The following will tell you whether or not all of the text is selected within a text input in all major browsers.

示例： http://www.jsfiddle.net/9Q23E/

代码：

function isTextSelected(input) {
    if (typeof input.selectionStart == "number") {
        return input.selectionStart == 0 && input.selectionEnd == input.value.length;
    } else if (typeof document.selection != "undefined") {
        input.focus();
        return document.selection.createRange().text == input.value;
    }
}