防止查看源代码进行复制的方法

参考：https://www.cnblogs.com/ypppt/p/12942773.html

<script language="javascript">
    function click(e) {
        if(document.all) {
            
            if(event.button == 2 || event.button == 3) {
                oncontextmenu = 'return false';
            }
        }
        if(document.layers) {
            if(e.which == 3) {
                oncontextmenu = 'return false';
            }
        }
    }
    if(document.layers) {
        document.captureEvents(Event.MOUSEDOWN);
    }
    document.onmousedown = click;
    document.oncontextmenu = new Function("return false;")
    document.onkeydown = document.onkeyup = document.onkeypress = function() {
        //123屏蔽F12,73屏蔽Ctrl+Shift+I,121屏蔽Shift+F10
        if(window.event.keyCode == 123 || window.event.keyCode == 73 || window.event.keyCode == 121) {
            window.event.returnValue = false;
            return(false);
        }
    }
</script>