Checkbox.js

/**
 * @class Ext.form.Checkbox
 * @extends Ext.form.Field
 * Single checkbox field.  Can be used as a direct replacement for traditional checkbox fields.
 * @constructor
 * Creates a new CheckBox
 * @param {Object} config Configuration options
 */
Ext.form.Checkbox = function(config){
    Ext.form.Checkbox.superclass.constructor.call(this, config);
    this.addEvents({
        /**
         * @event check
         * Fires when the checkbox is checked or unchecked
	     * @param {Ext.form.Checkbox} this This checkbox
	     * @param {Boolean} checked The new checked value
	     */
        check : true
    });
};

Ext.extend(Ext.form.Checkbox, Ext.form.Field,  {
    /**
     * @cfg {String} focusClass The CSS class to use when the checkbox receives focus (defaults to 'x-form-check-focus')
     */
    focusClass : "x-form-check-focus",
    /**
     * @cfg {String} fieldClass The default CSS class for the checkbox (defaults to "x-form-field")
     */
    fieldClass: "x-form-field",
    /**
     * @cfg {Boolean} checked True if the the checkbox should render already checked (defaults to false)
     */
    checked: false,

    // private
    defaultAutoCreate : { tag: "input", type: 'checkbox', autocomplete: "off"},
    /**
     * @cfg {String} boxLabel The text that appears beside the checkbox
     */
    boxLabel : undefined,
    /**
     * @cfg {String} inputValue The value that should go into the generated input element's value attribute
     */
// holder
/***
     * Sets the width and height of the checkbox wrapper element
     * @param {Number} width New width in pixels
     * @param {Number} height New height in pixels
     */
    setSize : function(w, h){
        if(!this.wrap){
            this.width = w;
            this.height = h;
            return;
        }
        this.wrap.setSize(w, h);
        if(!this.boxLabel){
            this.el.alignTo(this.wrap, 'c-c');
        }
    },

    initEvents : function(){
        Ext.form.Checkbox.superclass.initEvents.call(this);
        this.el.on("click", this.onClick,  this);
        this.el.on("change", this.onClick,  this);
    },

    
    // private
    onRender : function(ct, position){
        Ext.form.Checkbox.superclass.onRender.call(this, ct, position);
        if(this.inputValue !== undefined){
            this.el.dom.value = this.inputValue;
        }
        this.wrap = this.el.wrap({cls: "x-form-check-wrap"});
        if(this.boxLabel){
            this.wrap.createChild({tag: 'label', htmlFor: this.el.id, cls: 'x-form-cb-label', html: this.boxLabel});
        }
        if(this.checked){
            this.setValue(true);
        }
    },

    // private
    initValue : Ext.emptyFn,

    /**
     * Returns the checked state of the checkbox.
     * @return {Boolean} True if checked, else false
     */
    getValue : function(){
        if(this.rendered){
            return this.el.dom.checked;
        }
        return false;
    },

    onClick : function(){
        if(this.el.dom.checked != this.checked){
            this.setValue(this.el.dom.checked);
        }
    },

    /**
     * Sets the checked state of the checkbox
     * @param {Boolean/String} checked True, 'true,' or '1' to check the checkbox, any other value will uncheck it
     */
    setValue : function(v){
        this.checked = (v === true || v === 'true' || v == '1');
        if(this.el && this.el.dom){
            this.el.dom.checked = this.checked;
        }
        this.fireEvent("check", this, this.checked);
    }
});