var portfolio_on = new Image();
portfolio_on.src = '/img/portfolio-on.png';

var portfolio_off = new Image();
portfolio_off.src = '/img/portfolio-off.png';


var servise_on = new Image();
servise_on.src = '/img/service-on.png';

var servise_off = new Image();
servise_off.src = '/img/service-off.png';


var company_on = new Image();
company_on.src = '/img/company-on.png';

var company_off = new Image();
company_off.src = '/img/company-off.png';


var contact_on = new Image();
contact_on.src = '/img/contact-on.png';

var contact_off = new Image();
contact_off.src = '/img/contact-off.png';

function bt_on(name){
	document[name].src = eval(name + '_on.src');
}

function bt_off(name){
	document[name].src = eval(name + '_off.src');
}