var http_request = false;

function prepare_requete() {

    http_request = false;

    if (window.XMLHttpRequest) { // Mozilla, Safari,...
        http_request = new XMLHttpRequest();
        if (http_request.overrideMimeType) {
            http_request.overrideMimeType('application/xml');
        }
    } else if (window.ActiveXObject) { // IE
        try {
            http_request = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e) {
            try {
            http_request = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e) {}
        }
    }

    if (!http_request) {
        alert('Giving up :( Cannot create an XMLHTTP instance');
        return false;
    }
}

http_request2=new Array();
function prepare_requete2(i) {
    http_request2[i] = false;

    if (window.XMLHttpRequest) { // Mozilla, Safari,...
        http_request2[i] = new XMLHttpRequest();
        if (http_request2[i].overrideMimeType) {
            http_request2[i].overrideMimeType('application/xml');
        }
    } else if (window.ActiveXObject) { // IE
        try {
            http_request2[i] = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e) {
            try {
            http_request2[i] = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e) {}
        }
    }

    if (!http_request2[i]) {
        alert('Giving up :( Cannot create an XMLHTTP instance');
        return false;
    }
}

function prepare_requete_post() {
  http_request = false;
  if (window.XMLHttpRequest) { // Mozilla, Safari,...
     http_request = new XMLHttpRequest();
     if (http_request.overrideMimeType) {
     	// set type accordingly to anticipated content type
        //http_request.overrideMimeType('text/xml');
        http_request.overrideMimeType('text/html');
     }
  } else if (window.ActiveXObject) { // IE
     try {
        http_request = new ActiveXObject("Msxml2.XMLHTTP");
     } catch (e) {
        try {
           http_request = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e) {}
     }
  }
  if (!http_request) {
     alert('Cannot create XMLHTTP instance');
     return false;
  }
}