var rows = ['g1', 'g2'];

var rows = ['g1', 'g2', 'g3', 'g4'];

<script id="datascript" type="text/javascript" src="data1.js"></script>

onclick="datascript.src='data2.js';alert(rows);"

$('#datascript').remove();
$.getScript("data2.js", function(data, textStatus, jqxhr) {
   alert(rows);
});

// remove previous script element
var sElem = document.getElementById('datascript')
sElem.parentNode.removeChild(sElem);

// insert new script
var newScript = document.createElement('script');
newScript.type = 'text/javascript';
newScript.id = 'datascript';
newScript.onload= function() {
   alert(rows);
};
newScript.src = 'data2.js';
document.getElementsByTagName("head")[0].appendChild(newScript);