Thanks to C-Link I've solved this.
To be sure only the nodes are clickable I've wroted:
$("svg").find("g.node").click(function(){
alert("Lolol");
});
And it works fine.
Use find() method for more info visit this
For eg $("body").find("p").css("background-color","#f00");
sets all body's <p>
element background-color to red.
For your question try this:
$("svg").find("g").click(function(){
// your jquery code here
}
);