Form binding

[exo]

I'm sort of surprised noone has asked this before (or: I'm just really bad at searching the forums, in that case I apologize) but is there a simple, clean way to facilitate form binding within Ext? What I'm looking for is a standardized easy way of connecting a form to the back-end. I've noticed forms support 'actions' but I couldn't quite make out what they do or how they work. Some simple examples will be greatly appreciated.

[amon]

var loginObj = Class.create();
loginObj.prototype = {
	
	initialize : function() {
		
		Ext.onReady(this.create.bind(this), this, true);
	},
	
	create : function() {
		
	   Ext.QuickTips.init();
	   Ext.form.Field.prototype.msgTarget = 'side';
	    this.fs = new Ext.form.Form({
	        labelAlign: 'right',
	        labelWidth: 85,
	        url:'index.php',
	        method: 'POST',
	        buttonAlign: 'right',
	        baseParams: {module:'login'}
	    });
	
	    this.fs.fieldset(
	        {legend:'Login'},
	        new Ext.form.TextField({
	            fieldLabel: 'Username',
	            name: 'username',
	            id: 'username',
	            allowBlank:false,
	            blankText: 'Required!',
	            width:190
	        }),
	
	        new Ext.form.Field({
	            autoCreate : {tag: "input", type: "password", autocomplete: "off"},
	            cls: 'x-form-text',
	            fieldLabel: 'Password',
	            name: 'password',
	            id: 'password',
	            allowBlank:false,
	            blankText: 'Required!',
	            width:190
         	})
	    );
	
	    this.fs.addButton('Login',this.doLogin.bind(this));
	    this.fs.render('form-ct3');
	},
	
	doLogin : function() {
		this.fs.submit({
			success: function(){
			    // do something?
			    window.location.reload();
			},
			waitMsg : 'Logging in...',
			method: 'POST'
		});
	}
};
var login = new loginObj();

Note: this.<functionname>.bind(this) is prototype feature.
But in this case: this.fs.submit() posts (over XHR) the form data to the 'url' URL. (See the form constructor!).


Or, here is another example:
http://extjs.com/forum/showthread.php?t=4403