ExtJS perguntas e respostas de entrevista
Pergunta 46. How to register callbacks to the load and exception events of the JsonStore?
var grid = new Ext.grid.GridPanel({
store: new Ext.data.JsonStore({
[...]
listeners: {
load: this.onLoadSuccess.crateDelegate(this),
exception: this.onLoadException.createDelegate(this)
}
}),
onLoadSuccess: function () {
// success
},
onLoadException: function () {
// error
},
[...]
}
Pergunta 47. How to write extjs decode()?
var json = Ext.decode(response.responseText);
Ext.Msg.alert('Error', json.error);
Pergunta 48. Why did you choose Ext JS?
Given the wide range of JavaScript libraries available it was important to choose the right one. We needed to choose a library that was consistent in the way that it presents information to the user, but also consistent in the way that you code using the library.
With all Ext components extending the ‘Observable’ class we had the ability to write consistent code in an event-driven manner, much like writing a desktop application, not easily achieved with other libraries. What’s more is that we knew it would work cross-browser, again something not easily achieved that saves countless hours on large projects.
Pergunta 49. What features could we add to Ext to make building a rich application like PLANet easier in the future?
Once an application gets over a certain size, and customer releases become more frequent, the burden of testing the application starts to take its toll. An Ext supported test suite would save huge amounts of time. The current problem of test suites with Ext is being able to reliably predict the automatic ids that Ext generates for page elements. Test tools are beginning to implement support for CSS selectors to overcome this problem, but few currently exist. Ext could provide better documentation on how to build better test cases with Ext so that more time can be spent on development rather than testing.
Pergunta 50. Difference between ExtJS and JQuery?
ExtJs and JQuery are kind of apples and oranges. You can compare Ext Core to JQuery, and ExtJs to JQuery UI.
Ext JS is a full-fledged widget library while jQuery (not jQuery UI) and Mootools are JavaScript frameworks that help with DOM manipulation etc.
Whilst jQuery and Mootools help with the general workings of a site.
jQuery UI is a much less rich set of components.
Ext JS seems to be focussed on tables and storing data, plus manipulating it.
Mais uteis segundo os usuarios:
- Why did you choose Ext JS?
- Why do we need javascript Library?
- What is syntax for Extjs Button click event?
- How to access DOM element using EXTJS?
- Integration of Web development server-side frameworks with Ext JS?