hasegawayosuke / npwin32

NPAPI DLL for Win32 API

NPAPI DLL for calling DLL functions inside JavaScript.

Sample

<embed type="application/x-win32api-dynamic-call" id="p" hidden="true" />
<script type="text/javascript">
function foo(){
    var r = "";
    var plugin = document.getElementById( "p" );

    // import functions
    var MessageBox = plugin.import( "user32.dll", "INT MessageBoxW( DWORD, LPCWSTR, LPCWSTR, UINT )" ); 
    var GetWindowsDirectory = plugin.import( "kernel32.dll", "UINT GetWindowsDirectoryW( LPWSTR, UINT )" );
    var GetDiskFreeSpace = plugin.import( "kernel32.dll", "BOOL GetDiskFreeSpaceW( LPCWSTR, LPDWORD, LPDWORD, LPDWORD, LPDWORD )" );

    var MB_ICONINFORMATION = 64;

    // basic usage
    if( MessageBox ){
        MessageBox( 0, "hello, world", "chrome", MB_ICONINFORMATION );
    }

    // example of retrieving integer
    if( GetDiskFreeSpace ){
        var SectorsPerCluster = 0 , BytesPerSector = 1, NumberOfFreeClusters = 1, TotalNumberOfClusters = 1;
        if( GetDiskFreeSpace( "C:\\", SectorsPerCluster, BytesPerSector, NumberOfFreeClusters, TotalNumberOfClusters ) ){
            r = "SectorsPerCluster:" + GetDiskFreeSpace.arg( 1 ) + "\nBytesPerSector:" + GetDiskFreeSpace.arg( 2 ) +
                "\nNumberOfFreeClusters:" + GetDiskFreeSpace.arg( 3 ) + "\nTotalNumberOfClusters:" + GetDiskFreeSpace.arg( 4 ) + "\n";
        };
    }

    // example of retrieving string
    var buf = new Array( 257 ).join( " " );// space * 256
    if( GetWindowsDirectory ){
        GetWindowsDirectory( buf, buf.length );
        r += "Windows directory:'" + GetWindowsDirectory.arg( 0 ) + "'\n";
    }

    if( MessageBox ){
        MessageBox( 0, r, "Chrome", MB_ICONINFORMATION );
    }

    // using callback
    var maxEnumCount = 10;
    r = "hwnd : title\n";
    var EnumWindows = plugin.import( "user32.dll", "BOOL EnumWindows( CALLBACK, DWORD )" );
    var GetWindowText = plugin.import( "user32.dll", "INT GetWindowTextW( DWORD, LPWSTR, INT )" );
    var callback = plugin.callback( 
        function ( hwnd, lparam ){
            var buf = new Array( 257 ).join( " " );// space * 256
            if( GetWindowText( hwnd, buf, 256 ) ){
                r += hwnd + " : " + GetWindowText.arg( 1 ) + "\n";
                maxEnumCount--;
            }
            return maxEnumCount > 0;
        },
        "BOOL (DWORD, DWORD)"
    );
    EnumWindows( callback, 0x1234 );
    alert( r );
}
</script>

License

the MIT License

Author

Yosuke HASEGAWA <utf-8.jp>