// JavaScript Document

function createXmlHttpRequestObject(){
		//creates XMLHttpRequest object if it is possible
		var xmlHttp;
		try {
				//should work on all browsers except IE6 or older
				xmlHttp = new XMLHttpRequest();
		}
		catch (e){
				//browser is IE6 or older
				try {
						xmlHttp = new ActiveXObject("Microsoft.XMLHttp");
				}
				catch (e){
				//ignore error
				}
		}
		if (!xmlHttp)
				alert ("Error creating the XMLHttpRequest object.");
		else
				return xmlHttp;
}


var http_request;

    function zoom(scale, id, page) {
     
        var http_request = createXmlHttpRequestObject();
        var request = 'zoom=' + scale + '&id=' + id + '&page=' + page;
        
        http_request.onreadystatechange = function() { getResult(http_request); };
        http_request.open('POST', '/getResult.php', true);
        http_request.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        http_request.send(request);
   }

    function getResult(http_request) {
        if (http_request.readyState == 4) {
            if (http_request.status == 200) {
                
                var response = http_request.responseText
                //process response
                respDiv = document.getElementById('sem');
                respDiv.innerHTML = "";
                respDiv.innerHTML += response;
                //alert(response);

            } else {
                respDiv = document.getElementById('sem');
                respDiv.innerHTML = "";
                respDiv.innerHTML += 'Obrázek nebyl nalezen.';
            }
        }
    }