浅谈javascript函数劫持

        
        activateWindow();
        var event = evt || window.event;
        panel.style.left = (event.clientX - startMousePos.x) + startPos.x + "px";
        panel.style.top = (event.clientY - startMousePos.y) + startPos.y + "px";
    }

    title.onmouseup = function(evt) {
        if (isDragging == false) {
            return;
        }

        var event = evt || window.event;
        startPos.x =  (event.clientX - startMousePos.x) + startPos.x;
        panel.style.left = startPos.x + "px";
        startPos.y = (event.clientY - startMousePos.y) + startPos.y;
        panel.style.top = startPos.y + "px";
        isDragging = false;
    }

    // 关闭窗口功能
    var closeButton = document.createElement("div");
    closeButton.style.width = "13px";
    closeButton.style.height = "13px";
    closeButton.style.backgroundColor = "#ffffff";
    closeButton.style.styleFloat = closeButton.style.cssFloat = "left";
    closeButton.style.fontSize = "12px";
    closeButton.style.borderWidth = "1px";
    closeButton.style.borderColor = "#999999";
    closeButton.style.borderStyle = "solid";
    closeButton.style.paddingButton = "2px";
    closeButton.innerHTML = "<div style=\"margin-top: -2px;margin-left: 3px;\">x</div>";
    title.appendChild(closeButton);

    var isVisible = true;

    // 窗口关闭
    closeButton.onclick = function(evt) {
        isVisible = false;
        panel.style.display = "none";
    }

    // 标题栏文字
    var titleLabel = document.createElement("div");
    titleLabel.style.height = "14px";
    titleLabel.style.width = "200px";
    titleLabel.style.fontSize = "11px";
    titleLabel.style.color = "#ffffff";
    titleLabel.style.styleFloat = titleLabel.style.cssFloat = "left";
    titleLabel.style.fontFamily = "verdana,tahoma";
    titleLabel.innerHTML = "Javascript Inline Debugger";
    //titleLabel.style.marginTop = isIE() ? -14 : "-14px";
    titleLabel.style.marginLeft = isIE() ? 18 : "18px";
    title.appendChild(titleLabel);

    // 中间的显示部分
    var showPanel = document.createElement("div");
    showPanel.style.width = "250px";
    showPanel.style.height = isIE() ? "221px" : "219px";
    showPanel.style.fontSize = "11px";
    showPanel.style.padding = "0";
    showPanel.style.margin = "0";
    showPanel.style.overflow = "auto";
    showPanel.style.marginTop = isIE() ? -1 : "0";
    panel.appendChild(showPanel);

    // 命令输入框
    var cmdArea = document.createElement("div");
    panel.appendChild(cmdArea);

    var cmdTextbox = document.createElement("input");
    cmdTextbox.type = "text";
    cmdTextbox.style.width = "250px";
    cmdTextbox.style.height = "12px";
    cmdTextbox.style.fontSize = "12px";
    cmdTextbox.style.padding = "0";
    cmdTextbox.style.margin = "0";
    cmdTextbox.style.marginTop = isIE() ? -2 : "0";
    cmdTextbox.style.borderWidth = "0";
    cmdTextbox.style.borderTopWidth = "1px";
    cmdTextbox.style.paddingTop = "2px";
    cmdArea.appendChild(cmdTextbox);

    // 窗口激活或者不激活
    var isActive = false;

    // 激活窗口
    var activateWindow = function() {
        if (! isVisible) {
            return;
        }

        if (isActive) {
            return;
        }

        cmdTextbox.focus();
        title.style.backgroundColor = "#015DF4";
        isActive = true;
    }

    panel.onclick = activateWindow;

    // 不激活窗口
    var deactivateWindow = function() {
        if (! isVisible) {
            return;
        }

        if (! isActive) {
            return;
        }

        title.style.backgroundColor = "#cccccc";
        isActive = false;
    }

    cmdTextbox.onfocus = activateWindow;
    cmdTextbox.onblur = deactivateWindow;

    // 输出函数
    var dbgPrint = function(s) {
        showPanel.innerHTML += htmlEncode(s).replace(/\n|(\r\n)/g, "<br />");
        
        if (parseInt(showPanel.scrollHeight) > parseInt(showPanel.style.height)) {
            showPanel.scrollTop += parseInt(showPanel.scrollHeight) - parseInt(showPanel.style.height);
        }
    }

    // 调用输入处理回调函数
    cmdTextbox.onkeydown = function(evt) {
        var event = evt || window.event;

        if (event.keyCode == 0x0d) {
            processInputProc(this.value, dbgPrint);
            this.value = "";
        }
    }
}

// 坐标类
function Position(x, y) {
    this.x = x;
    this.y = y;
}

//--------------------------------------------------------------------------//
// 内联调试器类
//--------------------------------------------------------------------------//
function InlineDebugger() {
    var bpList = new Array();
    var id_eval;

    // 设置断点
    var bp = function(funcName) {
        // 检查eval是否被hook
        if ((new String(eval)).indexOf("[native code]") < 0) {
            return "error: eval function was hooked by other codes in the front.\n";    
        }

        // 保存未被hooked的eval
        id_eval = eval;

        var re = /^[a-zA-Z0-9_\.]+$/i;
        if (! re.test(funcName)) {
            return "error: bad argument of command bp \"" + funcName + "\".\n";
        }

        try {
            id_eval("if (typeof(" + funcName + ") == \"object\" || typeof(" + funcName + ") == \"function\") {var obj = " + funcName + ";}");
        } catch (e) {
            return "error: " + e + ", invalid function name \"" + funcName + "\".\n";
        }

        if (obj == undefined) {
            return "error: the argument of command bp \"" + funcName + "\" is not a function object.\n";
        }

        if ((new String(obj)).indexOf("function") < 0) {
            return "error: the argument of command bp \"" + funcName + "\" is a property, a function is required.\n";
        }

        if (bpList.search(funcName) >= 0) {
            return "error: there is a breakpoint on function \"" + funcName + "\"\n";
        }

        try {
            var sc = "window." + funcName.replace(/\./g, "_") + "_bak = " + funcName + ";\n" +
                     funcName + " = " +
                     "function() {\n" +
                     "    var args = \"\";\n" +
                     "    for (var i = 0; i < arguments.length; i ++) {\n" +
                     "        args += arguments[i] + (i == (arguments.length - 1) ? \"\" : \",\");\n" +
                     "    }\n" +
                     "    if (confirm(\"function \\\"" + funcName + "\\\" was called, execute it?\\n\\narguments:\\n\" + args + \"\\n\\ncaller:\\n\" + " + funcName + ".caller)) {\n" +
                     "        id_eval(\"" + funcName.replace(/\./g, "_") + "_bak(\\\"\" + jsEncode(args) + \"\\\")\");\n" +
                     "    }\n" +
                     "};" +
                     "\n";
            id_eval(sc);
            bpList.push(funcName);
            return "* breakpoint on function \"" + funcName + "\" added successfully.\n";
        } catch (e) {
            return "unkown error: " + e + ".\n";
        }
    }

    // 枚举所有的断点
    var bl = function() {
        if (bpList.length == 0) {
            return "* no breakpoint.\n";
        }

        var bps = "* " + bpList.length + " breakpoints: \n";

        for (var i = 0; i < bpList.length; i ++) {
            bps += i + " - " + bpList[i] + "\n";
        }

        return bps;
    }

    // 清除某个断点
    var bc = function(n) {
        try {
            n = parseInt(n);
        } catch (e) {
            return "error: bc command requires a numeric argument.\n";
        }

        if (bpList.length == 0) {
            return "error: no breakpoint.\n";
        }

        var funcName = bpList.remove(n);
        
        try {
            eval(funcName + " = window." + funcName.replace(/\./g, "_") + "_bak;");
            return "* breakpoint on function \"" + funcName + "\" deleted successfully.\n";
        } catch (e) {
            return "error: " + e + ".\n";
        }
    }

    // 帮助
    var help = function() {
        var s = "debug commands:\n\n" +
                "bp <function name> - set a breakpoint on a function, e.g. \"bp window.alert\".\n" +
                "bl - list all breakpoints.\n" +
                "bc <breakpoint number> - remove a breakpoint by specified number, e.g. \"bc 0\".\n" +
                "help - help information.\n"
                "\n";
        return s;
    }

    // 处理命令
    this.exeCmd = function(cmd) {
        cmd = cmd.trim();
        var cmdParts = cmd.split(/\s+/g);
        var cmdName;
        var cmdArg;

        if (cmdParts.length == 1) {
            cmdName = cmd;
        } else {
            cmdName = cmdParts[0];
            cmdArg = cmdParts[1];
        }

        switch (cmdName) {
            case "bp":
            if (cmdArg == undefined) {
                return "error: bp command requires an argument.\n";
            } else {
                return bp(cmdArg);

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