Navegação sem refresh com IF para IE 7,8 e 9

 var $ajax_reload = jQuery.noConflict()
       $ajax_reload(document).ready(function(){
        var content = $ajax_reload('#lateral-esquerda');

        //pre carregando o gif
        loading = new Image(); loading.src = 'ico-loading.gif';
        $ajax_reload('#menu a').live('click', function( e ){
        e.preventDefault();
        content.html( '<div style=" width:500px; margin:30px 0 0 0; float:left; height:400px"><img src="js/ico-loading.gif" style="margin:80px 0 0 130px;  float:left" /></div>' );
            var href = $ajax_reload( this ).attr('href');
            $ajax_reload.ajax({
                url: href,
                success: function( response ){
                    //forçando o parser
                    var response = $ajax_reload( '<div>'+response+'</div>' );
                    var data = response.find('#lateral-esquerda').html();

    if(window.history.pushState) {
            //apenas atrasando a troca, para mostrarmos o loading
                    window.setTimeout( function(){
                        content.fadeOut('slow', function(){
                            content.html( data ).fadeIn();
                            var title = response.find('title').text();
                            document.title = title;
                                window.history.pushState( href, title, href )
                        });
                    }, 500 );
        } else {
                    //apenas atrasando a troca, para mostrarmos o loading
                    window.setTimeout( function(){
                        content.fadeOut('slow', function(){
                            content.html( data ).fadeIn();

                        });
                    }, 500 );


        // comando caso não funcione
        }


                }

            });

        });
    });