How to use phantomjs along with node.js for scrapping

I have installed node-phantom by npm install node-phantom but when I am running this code, it is giving Cannot find module 'webpage' this error

var webpage=require('webpage').create(),
url="http://ift.tt/15Xel71",
hrefs= new Array();
webpage.open(url,function(status){
if(status=="success"){
    var results = page.evaluate(function(){
        $("#endpoints").each(function() {
              hrefs.push($(this).attr("href"));
        });
        return hrefs;
    });
    console.log(JSON.stringify(results));
    phantom.exit();
}
});

Can anyone help me out with this problem