Passing multiple parameter in Url of a web service in angularjs

I want to call a url through my service in ionic project. the url should be like www.helloworld.com/getdetails?a=10&b=20&c=30

the service call is made like this

$http({
    method: "POST",
    url:"/getIdeaList",  
    params:{'a':10,'b':20,'c':30},
    headers: {
        'devicemetadata':deviceMetadata,
        'Encoding':"UTF-8",
        'deviceID':deviceID
    }
});

//getIdeaList is proxy for Url-www.helloworld.com/getdetails

I tried like the about but the its calling like this-www.helloworld.com/getdetails?a=10& amp;b=20& amp;c=30\n