AB.newSplash();                   
  
  AB.splashHtml (  ` 
    <h1> Password only Websocket boxes </h1>  
    A version of Websocket boxes that only certain users can join.  <br>
    You enter a password. You only join with users who enter the same password (not with all users of the World).  <br>
    The first user to run the World can enter any password! But other users must know what password they will use.
    <p>
	Enter password: 
	<input    style='width:25vw;'    maxlength='2000'   NAME="p"    id="p"       VALUE='' >  
	<button onclick='start();'  class=ab-normbutton >Start</button>
	<p>  
	<div id=errordiv name=errordiv> </div> ` );  
	

//--- start Socket -----------------------------------------------------
    	
    function start()        // user has entered a password 
    {
    	var  password =  jQuery("input#p").val();
    	password = password.trim();
    	
    	if ( ! alphanumeric ( password ) )
    	{
    	    $("#errordiv").html( "<font color=red> <B> Error: Password must be alphanumeric. </b></font> " );
    	    return;
    	}
    	
    	// else we have a password, start the socket run with this password 
        AB.socketStart ( password );  
        
        AB.removeSplash();   
    }
    
    
      
    function alphanumeric ( str ) 				// return if string is just alphanumeric   
    {
    	var rc = str.match(/^[0-9a-zA-Z]+$/); 			// start of line  "[0-9a-zA-Z]+"  end of line 
    	
    	if ( rc ) return true;
    	else      return false; 
    }