zoneminder/web/skins/classic/views/js/monitor.js

function updateMonitorDimensions( element )
{
    var form = element.form;
    var widthFactor = parseInt( defaultAspectRatio.replace( /:.*$/, '' ) );
    var heightFactor = parseInt( defaultAspectRatio.replace( /^.*:/, '' ) );

    if ( form.elements['preserveAspectRatio'].checked )
    {
        var monitorWidth = parseInt(form.elements['newMonitor[Width]'].value);
        var monitorHeight = parseInt(form.elements['newMonitor[Height]'].value);
        switch( element.name )
        {
            case 'newMonitor[Width]':
                if ( monitorWidth >= 0 )
                    form.elements['newMonitor[Height]'].value = Math.round((monitorWidth * heightFactor) / widthFactor);
                else
                    form.elements['newMonitor[Height]'].value = '';
                break;
            case 'newMonitor[Height]':
                if ( monitorHeight >= 0 )
                    form.elements['newMonitor[Width]'].value = Math.round((monitorHeight * widthFactor) / heightFactor);
                else
                    form.elements['newMonitor[Width]'].value = '';
                break;
        }
    }
    return( false );
}

function loadLocations( element )
{
    var form = element.form;
    var controlIdSelect = form.elements['newMonitor[ControlId]'];
    var returnLocationSelect = form.elements['newMonitor[ReturnLocation]'];

    returnLocationSelect.options.length = 1;
    //returnLocationSelect.options[0] = new Option( noneString, -1 );

    var returnLocationOptions = controlOptions[controlIdSelect.selectedIndex];
    if ( returnLocationOptions )
    {
        for ( var i = 0; i < returnLocationOptions.length; i++ )
        {
            returnLocationSelect.options[returnLocationSelect.options.length] = new Option( returnLocationOptions[i], i );
        }
    }
}

function initPage()
{
    var protocolSelector = $('contentForm').elements['newMonitor[Protocol]'];
    if ( $(protocolSelector).getTag() == 'select' )
        updateMethods( $(protocolSelector) );
}

window.addEvent( 'domready', initPage );