function search(defaultValue) {
	if(document.getElementById('search_box').value != "" && document.getElementById('search_box').value != defaultValue) {
		document.getElementById('search_form').action += document.getElementById('selection_box').options[document.getElementById('selection_box').selectedIndex].value + '/' + str_replace(' ', '+', document.getElementById('search_box').value) + '/'
		return true;
	} else {
		alert("Zadejte hledané slovo.");
		return false;
	}
}

function str_replace(search, replace, subject) {
    var f = search, r = replace, s = subject;
    var ra = is_array(r), sa = is_array(s), f = [].concat(f), r = [].concat(r), i = (s = [].concat(s)).length;
    while (j = 0, i--) {
        while (s[i] = s[i].split(f[j]).join(ra ? r[j] || "" : r[0]), ++j in f){};
    };
    return sa ? s : s[0];
}

function is_array( mixed_var ) {
    return ( mixed_var instanceof Array );
}

function change_img(src, resized) {
	var img = document.getElementById('main_image');
	img.src = src;
	if(resized) {
		img.style.width = "320px";
		img.style.height= "320px";
	}
}

function set_search_label(element, defaultValue) {
 	if(element.value==defaultValue) {
 		element.value='';
 	} else if(element.value=='') {
 		element.value=defaultValue;
 	}
 }
 
 function buy(url) {
 	location.href = url + '?koupit';
	return false;
 }