Placeholder in sencha

问题

I have a place holder which disappears only when the user starts typing. How to make it disappear when the user clicks on it.

                {
                    xtype: 'textfield',
                    id: 'road',
                    placeHolder :'Road',
                    label: 'Road'

                }

Please do help.

来源：https://stackoverflow.com/questions/10026082/placeholder-in-sencha