var ajax;

function mostraCidades(id)
{
    this.location = "#" + "divMostra";

    ajax = funcaoAjax()

    var get = "mostra_cobertura.php"
    get = get + "?id_estado=" + id
    get = get + "&sid=" + Math.random()
    ajax.onreadystatechange = stateChanged
    ajax.open("GET", get, true)
    ajax.send(null)

    function stateChanged()
    {
            switch (ajax.readyState)
        {
             case 1:
                  document.getElementById("divMostra").innerHTML = "<p>&nbsp;</p><p>&nbsp;</p><p align='center'><img src='../images/ajax.gif' width='50' height='50' /></p>";
                  break;
             case 4:
                  if (ajax.readyState == 4 || ajax.readyState == "complete") {
                                      document.getElementById("divMostra").innerHTML = ajax.responseText;
                              }
                              break;
                    default:
                                     document.getElementById("divMostra").innerHTML = "<p><b>Lamento...<br /><p>problemas !</p></b></p>";
        }
    }

}

function funcaoAjax()
{
	var ajax = null;

	try {
		ajax = new XMLHttpRequest();
		} catch(e) {
			try {
				ajax = new ActiveXObject("Msxml2.XMLHTTP");
			} catch(e) {
				try {
						ajax = new ActiveXObject("Microsoft.XMLHTTP");
				} catch(E) {
						alert("Use um navegador descente, recomendo MOZILLA FIREFOX");
						return false;
				}
			}
		}
	return ajax;
}