function init(){
    var elem1 = document.getElementById('lron');
    elem1.addEventListener('click',funclron);
    var elem2 = document.getElementById('lroff');
    elem2.addEventListener('click',funclroff); 
    var elem3 = document.getElementById('upon');
    elem3.addEventListener('click',funcudon);
    var elem4 = document.getElementById('upoff');
    elem4.addEventListener('click',funcudoff);
}

function funclron(){
	browser.tabs.executeScript({
         code: "document.body.style.transform = 'rotateY(180deg)';"
	});
}

function funclroff(){
	browser.tabs.executeScript({
        code: "document.body.style.transform = 'rotateY(0deg)';"
	});
}


function funcudon(){
	browser.tabs.executeScript({
        code: "document.body.style.transform = 'rotateX(180deg)';"
	});
}

function funcudoff(){
	browser.tabs.executeScript({
        code: "document.body.style.transform = 'rotateX(0deg)';"
	});
}


document.addEventListener('DOMContentLoaded', init);