javascript 实现禁止右键，复制，选取文本 (兼容firefox，IE，chrome等主流浏览器)

body{
    -webkit-touch-callout: none;  
    -webkit-user-select: none;  
    -khtml-user-select: none;  
    -moz-user-select: none;  
    -ms-user-select: none;  
    user-select: none;  
}

function iEsc(){ return false; }
function iRec(){ return true; }
function DisableKeys() {
    if(event.ctrlKey || event.shiftKey || event.altKey)  {
    window.event.returnValue=false;
    iEsc();}
}

document.ondragstart=iEsc;
document.onkeydown=DisableKeys;
document.oncontextmenu=iEsc;

if (typeof document.onselectstart !="undefined") document.onselectstart=iEsc;
else
{
    document.onmousedown=iEsc;
    document.onmouseup=iRec;
}

function DisableRightClick(e)
{
    if (window.Event){ if (e.which == 2 || e.which == 3) iEsc();}
    else
        if (event.button == 2 || event.button == 3)
        {
            event.cancelBubble = true
            event.returnValue = false;
            iEsc();
        }
}