import {Directive, ElementRef} from 'angular2/core';
@Directive({
    selector: '[Slidernav]'
})
export class Slidernav {
    constructor(private element: ElementRef) {
        console.log('Slider Run');
    }
}

<div slidernav>Some content</div>

selector: '[Slidernav]'
...
<div slidernav>Some content</div>

selector: '[Slidernav]'
...
<div Slidernav>Some content</div>

selector: '[slidernav]'
...
<div slidernav>Some content</div>