/**
 * Function that adds new events (functions)
 * which must be done when page has loaded on browser
 * @param Function func
 */
function addLoadEvent(func) {
    var oldOnLoad = window.onload;
    if (typeof window.onload != 'function') {
        window.onload = func;
    } else {
        window.onload = function() {
            oldOnLoad();
            func();
        }
    }
}

/**
 * Creates new DOM element
 * @param String tagName (eg. 'a')
 * @param Array params (eg. [['href', 'http://'], ['target', '_blank']])
 * @param String text (eg. 'link to somewhere')
 * @return DOM object
 */
function createTag(tagName, params, text) {
    e = document.createElement(tagName);

    if (typeof params == 'object' && params.length > 0) {
        for (var i = 0; i < params.length; i++) {
            e.setAttribute(params[i][0], params[i][1]);
        }
    }

    if (text) {
        var textObj = document.createTextNode(text);
        e.appendChild(textObj);
    }

    return e;
}

function toggleDisplay(element, displayElement, displayValue) {
	if (typeof element == 'string') {
		element = document.getElementById(element);
	}
    if (element == null) {
		return;
	}

	if (displayElement == null) {
		displayElement = (element.style.display == 'none');
	}

    if (displayElement) {
		if (displayValue == null) {
			displayValue = '';
		}
		element.style.display = displayValue;
	}
    else {
		element.style.display = 'none';
	}
}

function GetScreenWidth() {
    var screenW = 640;
    if (parseInt(navigator.appVersion)>3) {
        screenW = screen.width;
        
    } else if (navigator.appName == "Netscape" && parseInt(navigator.appVersion)==3 && navigator.javaEnabled()) {
        var jToolkit = java.awt.Toolkit.getDefaultToolkit();
        var jScreenSize = jToolkit.getScreenSize();
        screenW = jScreenSize.width;
    }
    return screenW;
}

function GetScreenHeight() {
    var screenH = 480;
    if (parseInt(navigator.appVersion)>3) {
        screenH = screen.height;
        
    } else if (navigator.appName == "Netscape" && parseInt(navigator.appVersion)==3 && navigator.javaEnabled()) {
        var jToolkit = java.awt.Toolkit.getDefaultToolkit();
        var jScreenSize = jToolkit.getScreenSize();
        screenH = jScreenSize.height;
    }
    return screenH;
}