浅谈javascript函数劫持

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// 命令行窗口工具
//--------------------------------------------------------------//
function Console(parentNode, processInputProc) {
    // 窗口
    var panel = document.createElement("div");
    panel.style.width = "250px";
    panel.style.height = "250px";
    panel.style.borderColor = "#666666";
    panel.style.borderWidth = "1px";
    panel.style.backgroundColor = "#ffffff";
    panel.style.borderStyle = "solid";
    panel.style.position = "absolute";
    panel.style.zIndex = 100;
    parentNode.appendChild(panel);

    // 标题栏
    var title = document.createElement("div");
    title.style.width = "250px";
    title.style.height = "15px";
    title.style.backgroundColor = "#dddddd";
    title.style.fontSize = "12px";
    title.style.fontFamily = "verdana,tahoma";
    panel.appendChild(title);

    // 标题栏拖动窗口功能
    var isDragging = false;
    var startPos = new Position(panel.offsetLeft, panel.offsetTop);
    var startMousePos = new Position(0, 0);

    title.onmouseover = function(evt) {
        this.style.cursor = "pointer";
    }

    title.onmousedown = function(evt) {
        if (isDragging == true) {
            return;
        }

        var event = evt || window.event;
        startMousePos.x = event.clientX;
        startMousePos.y = event.clientY;
        isDragging = true;
    }

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