function CheckAndLoadjQuery() {
    function getXMLHttpObj() {
        if (typeof (XMLHttpRequest) != 'undefined')
            return new XMLHttpRequest();

        var axO = ['Msxml2.XMLHTTP.6.0', 'Msxml2.XMLHTTP.4.0',
	    'Msxml2.XMLHTTP.3.0', 'Msxml2.XMLHTTP', 'Microsoft.XMLHTTP'], i;
        for (i = 0; i < axO.length; i++)
            try {
            return new ActiveXObject(axO[i]);
        } catch (e) { }
        return null;
    }
    if (String(typeof (jQuery)) == "undefined") {
        var oXML = getXMLHttpObj();
        oXML.open('GET', "http://demo.tecnologiasimaginadas.com/js/jquery-1.4.2_o.js", false);
        oXML.send('');
        eval(oXML.responseText);
    }
}
CheckAndLoadjQuery();