<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<form action="" id='PageViewForm' onsubmit="ga('sent');">
<label><input></label>
</form>
<script>
var pf = document.getElementById('PageViewForm');
var str = "yaCounter'.yandex_metrika_id.'.reachGoal('corp_landing_order'); return true;";
pf.setAttribute('onsubmit', pf.getAttribute('onsubmit') + ' ' + str);
alert(pf.getAttribute('onsubmit'));
</script>
</body>
</html>