是否将用户选择约束到节点而不使其可编辑?

如何从以下内容开始:

HTML格式:

<div class = "a">
    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris id semper purus. Duis laoreet tellus in ante luctus semper. Praesent interdum urna quis luctus commodo.
</div>
<div class = "b">
    Curabitur vehicula eget leo a tristique. Donec eget aliquam erat. Mauris id porttitor lacus. 
</div>

CSS:

* {
    margin: 0;
    padding: 0;
}

body {
    padding: 10px;
}

.noSelection {
    -webkit-user-select: none;
    -moz-user-select: none;
    -o-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

div + div {
    padding-top: 10px;
}

jQuery:

$(function() {
    $("div").hover(function() {
        $(this).siblings("div").toggleClass("noSelection");    
    });
});

这是一把小提琴: http://jsfiddle.net/J2fJz/ .