//js 屏蔽

window.document.oncontextmenu = function () { event.returnValue = false; }//屏蔽鼠标右键

window.document.onselectstart = function () { event.returnValue = false; }//屏蔽鼠标选择

window.window.onhelp = function (){return false } //屏蔽F1帮助

window.document.onmousewheel = function ()//屏蔽Shift+滚轮,Ctrl+滚轮

{

    if (event.shiftKey || event.ctrlKey) {

        event.keyCode = 0;

        event.returnValue = false;

    }

}

window.document.onkeydown = function()

{

    if ((window.event.altKey) &&

        ((window.event.keyCode == 37) ||   //屏蔽 Alt+ 方向键 ←

            (window.event.keyCode == 39)))   //屏蔽 Alt+ 方向键 →

    {

        event.returnValue = false;

    }

    if ((event.keyCode == 116) ||                 //屏蔽 F5 刷新键

        (event.ctrlKey && event.keyCode == 82)) { //Ctrl + R

        event.keyCode = 0;

        event.returnValue = false;

    }

    if (event.keyCode == 32 || event.keyCode == 8)    //屏弊空格键,后退键

    {

        if (!(event.srcElement.tagName == "INPUT" && event.srcElement.type == "text") && event.srcElement.tagName != "TEXTAREA") {

            event.keyCode = 0;

            event.returnValue = false;

        }

    }

    //屏蔽F12

    if (window.event && window.event.keyCode == 123) {

        event.keyCode = 0;

        event.returnValue = false;

        return false;

    }

    if (event.keyCode == 27) { event.keyCode = 0; event.returnValue = false; }  //屏蔽ESC

    if (event.keyCode == 114) { event.keyCode = 0; event.returnValue = false; }  //屏蔽F3

    if (event.keyCode == 122) { event.keyCode = 0; event.returnValue = false; }  //屏蔽F11

    if (event.ctrlKey && event.keyCode == 67) { event.keyCode = 0; event.returnValue = false; }    //屏蔽 Ctrl+c

    if (event.ctrlKey && event.keyCode == 86) { event.keyCode = 0; event.returnValue = false; }    //屏蔽 Ctrl+v

    if (event.ctrlKey && event.keyCode == 70) { event.keyCode = 0; event.returnValue = false; }    //屏蔽 Ctrl+f

    if (event.ctrlKey && event.keyCode == 87) { event.keyCode = 0; event.returnValue = false; }    //屏蔽 Ctrl+w

    if (event.ctrlKey && event.keyCode == 69) { event.keyCode = 0; event.returnValue = false; }    //屏蔽 Ctrl+e

    if (event.ctrlKey && event.keyCode == 72) { event.keyCode = 0; event.returnValue = false; }    //屏蔽 Ctrl+h

    if (event.ctrlKey && event.keyCode == 73) { event.keyCode = 0; event.returnValue = false; }    //屏蔽 Ctrl+i

    if (event.ctrlKey && event.keyCode == 79) { event.keyCode = 0; event.returnValue = false; }    //屏蔽 Ctrl+o

    if (event.ctrlKey && event.keyCode == 76) { event.keyCode = 0; event.returnValue = false; }    //屏蔽 Ctrl+l

    if (event.ctrlKey && event.keyCode == 80) { event.keyCode = 0; event.returnValue = false; }    //屏蔽 Ctrl+p

    if (event.ctrlKey && event.keyCode == 66) { event.keyCode = 0; event.returnValue = false; }    //屏蔽 Ctrl+b

    if (event.ctrlKey && event.keyCode == 78) { event.keyCode = 0; event.returnValue = false; }  //屏蔽 Ctrl+n

}