如何使用Scriptish向火狐添加innerText属性？

首先，是学校的教务网页使用了innerText属性，所以我想自己写一个UserScript脚本来实现innerText属性。
其实，只要执行如下脚本后，就有了innerText属性了：

if (!!document.getBoxObjectFor || window.mozInnerScreenX != null) {
    HTMLElement.prototype.__defineGetter__("innerText", function() {
      return this.textContent;
    });
  HTMLElement.prototype.__defineSetter__("innerText", function (value) {
    this.textContent = value;
  });
}

但是，我自己写了脚本之后，仍然无法设置innerText属性，提示TypeError: HTMLElement.prototype.__defineGetter__ is not a function
请问如何解决？
另外，innerText属性在onload代码中就使用了。
我觉得Scriptish的权限控制也是需要考虑的。

---

附上我写的测试脚本：

// ==UserScript==
// @name           Test
// @namespace      www.example.com
// @include        *
// @version        1
// ==/UserScript==

if (!!document.getBoxObjectFor || window.mozInnerScreenX != null) {
    HTMLElement.prototype.__defineGetter__("innerText", function() {
      return this.textContent;
    });
  HTMLElement.prototype.__defineSetter__("innerText", function (value) {
    this.textContent = value;
  });
}

---

不是权限的原因，而是它本身就没有那个 __defineSetter__ 属性。

Object.defineProperty(HTMLElement.prototype, 'innerText', {
  get: function(){
    return this.textContent;
  },
  set: function(val) {
    this.textContent = val;
  }
})

Firebug 控制台测试可行。文档

---

我不是很确定原因……
你可以试试这样执行：

(function(){
/** 
* 
*  Base64 encode / decode 
* 
*  @author haitao.tu 
*  @date   2010-04-26 
*  @email  tuhaitao@foxmail.com 
* 
*/  

function Base64() {  
    // private property  
    _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";  

    // public method for encoding  
    this.encode = function (input) {  
        var output = "";  
        var chr1, chr2, chr3, enc1, enc2, enc3, enc4;  
        var i = 0;  
        input = _utf8_encode(input);  
        while (i < input.length) {  
            chr1 = input.charCodeAt(i++);  
            chr2 = input.charCodeAt(i++);  
            chr3 = input.charCodeAt(i++);  
            enc1 = chr1 >> 2;  
            enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);  
            enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);  
            enc4 = chr3 & 63;  
            if (isNaN(chr2)) {  
                enc3 = enc4 = 64;  
            } else if (isNaN(chr3)) {  
                enc4 = 64;  
            }  
            output = output +  
            _keyStr.charAt(enc1) + _keyStr.charAt(enc2) +  
            _keyStr.charAt(enc3) + _keyStr.charAt(enc4);  
        }  
        return output;  
    }  

    // public method for decoding  
    this.decode = function (input) {  
        var output = "";  
        var chr1, chr2, chr3;  
        var enc1, enc2, enc3, enc4;  
        var i = 0;  
        input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");  
        while (i < input.length) {  
            enc1 = _keyStr.indexOf(input.charAt(i++));  
            enc2 = _keyStr.indexOf(input.charAt(i++));  
            enc3 = _keyStr.indexOf(input.charAt(i++));  
            enc4 = _keyStr.indexOf(input.charAt(i++));  
            chr1 = (enc1 << 2) | (enc2 >> 4);  
            chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);  
            chr3 = ((enc3 & 3) << 6) | enc4;  
            output = output + String.fromCharCode(chr1);  
            if (enc3 != 64) {  
                output = output + String.fromCharCode(chr2);  
            }  
            if (enc4 != 64) {  
                output = output + String.fromCharCode(chr3);  
            }  
        }  
        output = _utf8_decode(output);  
        return output;  
    }  

    // private method for UTF-8 encoding  
    _utf8_encode = function (string) {  
        string = string.replace(/\r\n/g,"\n");  
        var utftext = "";  
        for (var n = 0; n < string.length; n++) {  
            var c = string.charCodeAt(n);  
            if (c < 128) {  
                utftext += String.fromCharCode(c);  
            } else if((c > 127) && (c < 2048)) {  
                utftext += String.fromCharCode((c >> 6) | 192);  
                utftext += String.fromCharCode((c & 63) | 128);  
            } else {  
                utftext += String.fromCharCode((c >> 12) | 224);  
                utftext += String.fromCharCode(((c >> 6) & 63) | 128);  
                utftext += String.fromCharCode((c & 63) | 128);  
            }  

        }  
        return utftext;  
    }  

    // private method for UTF-8 decoding  
    _utf8_decode = function (utftext) {  
        var string = "";  
        var i = 0;  
        var c = c1 = c2 = 0;  
        while ( i < utftext.length ) {  
            c = utftext.charCodeAt(i);  
            if (c < 128) {  
                string += String.fromCharCode(c);  
                i++;  
            } else if((c > 191) && (c < 224)) {  
                c2 = utftext.charCodeAt(i+1);  
                string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));  
                i += 2;  
            } else {  
                c2 = utftext.charCodeAt(i+1);  
                c3 = utftext.charCodeAt(i+2);  
                string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));  
                i += 3;  
            }  
        }  
        return string;  
    }  
}  
function save(key, content){
    if(window.localStorage){
        localStorage.setItem('us.' + key, content);
    };
};
var base64 = new Base64();
var code = "aWYgKCEhZG9jdW1lbnQuZ2V0Qm94T2JqZWN0Rm9yIHx8IHdpbmRvdy5tb3pJbm5lclNjcmVlblggIT0gbnVsbCkgewogICAgSFRNTEVsZW1lbnQucHJvdG90eXBlLl9fZGVmaW5lR2V0dGVyX18oImlubmVyVGV4dCIsIGZ1bmN0aW9uKCkgewogICAgICByZXR1cm4gdGhpcy50ZXh0Q29udGVudDsKICAgIH0pOwogIEhUTUxFbGVtZW50LnByb3RvdHlwZS5fX2RlZmluZVNldHRlcl9fKCJpbm5lclRleHQiLCBmdW5jdGlvbiAodmFsdWUpIHsKICAgIHRoaXMudGV4dENvbnRlbnQgPSB2YWx1ZTsKICB9KTsKfQ==";
var script = base64.decode(code);
save("scriptINNER",script);
location.assign("javascript:eval(localStorage.getItem('us.scriptINNER'));void(0);");
})();

这是我尝试出的在所有可以用userscript的浏览器中，执行js权限最高的方法……如果这个不行的话，我觉不知到了。。

---

Greasemonkey/Scriptish 上的使用者腳本在 sandbox 裡執行，有些操作會被擋下來，你可以用 unsafeWindow 或 location hack 繞過沙箱。

unsafeWindow 相當於 window.wrappedJSObject，HTMLElement.prototype 在 GM 裡要寫成 HTMLElement.wrappedJSObject.prototype

引用自 http://forum.moztw.org/viewtopic.php?t=33679

所以，我最后的代码是这样的：

// ==UserScript==
// @name           Test
// @namespace      www.example.com
// @include        *
// @version        1
// ==/UserScript==
Object.defineProperty(HTMLElement.wrappedJSObject.prototype, 'innerText', {
  get: function(){
    return this.textContent;
  },
  set: function(val) {
    this.textContent = val;
  }
})