sign-in.component.ts

login()
    {
        console.log(this.username+this.password)

        this.dataService.authenticate(this.username, this.password)
        .subscribe(
            (result) => {
               this.profile = result.data;
                console.log(result);
            }

        )

           }
data-service.ts
authenticate(username: string, password: string)
    {
            let headers = new Headers();
            //headers.append('Content-Type', 'application/json');
            headers.append('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
            var data = { username: username, password: password }
            //console.log(data);
            //console.log(JSON.stringify(data));
            return this.http.post('http://localhost/api/select.php/',JSON.stringify(data),headers).map(res => res.json());


    }

select.php
<?hphp
$postdata = file_get_contents("php://input");
    $request = json_decode($postdata);
    $username = $request->username;
    $password = $request->password;


    echo "$username"
?>