JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://cdn.sencha.io/ext-4.1.1-gpl/resources/css/ext-all.css">

JavaScript

// ExtJS window with form.

Ext.create('Ext.window.Window', {
    title: 'This is a Window with a Form',
    height: 200,
    width: 400,
    layout: 'fit',
    items: {  
        id: 'admin-win',
        title: 'Add administration users',
        width: 740,
        height: 480,
        iconCls: 'icon-grid',
        animCollapse: false,
        constrainHeader: true,
        xtype: 'form',
        bodyPadding: 15,
        url: 'save-form.php',
        items: [{
            xtype: 'textfield',
            fieldLabel: 'Field',
            name: 'theField',
            allowBlank: false
        }],
        buttons: [{
            text: 'Submit',
            handler: function() {
                var form = this.up('form').getForm();
                if (form.isValid()) {
                    form.submit({
                        success: function(form, action) {
                           Ext.Msg.alert('Success', action.result.message);
                        },
                        failure: function(form, action) {
                            Ext.Msg.alert('Failed', action.result ? action.result.message : 'No response');
                        }
                    });
                } else {
                    Ext.Msg.alert( "Error!", "Your form is invalid!" );
                }
            }
        }]
    }
}).show();