检验你的前端基础——Sit the test

　　前端小学生向大家推荐一个网站：Sit the test。如果你是一名前端工程师或者立志于此，不妨试试此网站上面的测验题。

发现

　　十几天前，我在奇舞周刊的一篇文章中，发现了一个国外的技能测试网站：Sit the test。测试分为HTML Core，CSS Core，CSS Core(practice)和JavaScript Core四部分，每种测试有25道题，限时30分钟。有了国内大牛的博客推荐，让我对测试题的含金量十分信服，当时我迫于证明自己，马上抽出时间挨着做了一遍：

　　做完就傻眼了，25题错7道，好像拿捏不准的全错了。题确确实实只是基础题，但是我没仔细看过W3C Standers，凭项目经验以及看过一些进阶书籍硬是把“基础送分题”变成了“附加题”。

分享

　　让人比较郁闷的是，除了CSS Core(practice)，其它三个测试只给出正确率，具体哪道做错了根本不告诉你，更别说正确答案应该是什么了。并且一个星期内只能参加一次测验，真是神奇极了。熟知测试规则后，我把自己做的题全都截图保存了下来，抽空仔细推敲了一遍。下面我抛砖引玉，将一些确定做错的题拿出来分享给大家。（答案放在最后，我无法将所有题的答案分享出来，因为最近我又进行了一遍测试，发现原题，题的顺序以及选项的顺序都会变）

　　1. Which of the following CSS measurements is the smallest in terms of physical size on a typical desktop display? Assume only default browser styles are in effect.

　　　　A：1ex　　B：1px　　C：1pt　　D：1em

　　2. Your site’s stylesheet contains two rules with exactly the same selector. Which of the following statements correctly describes how this code will apply to a web page?

　　　　A：Both rules apply to all matching elements, with the second rule overriding the first.

　　　　B：The second rule takes precedence, and the browser ignores the first.

　　3. Which of the following CSS color codes denotes a color that contains twice as much red as it does blue?

　　　　A：#7F0BFE　　B：#102005　　C：#AACC55　　D：#221144

　　4. When you specify a percentage value for margin-top on an element, how is this margin’s actual size calculated?

　　　　A：As a percentage of the width of the containing block.

　　　　B：As a percentage of the height of the containing block.

　　5. In a CSS color code such as #f06523.what does it mean if the code is composed of three identical pairs of digits(i.e. #XYXYXY)?

　　　　A：the color code will have the same brightness if inverted.

　　　　B：the color code represents a web-safe color.

　　　　C：the color code represents a shade of gray.

　　　　D：the color code has a complementary color with the digits inverted.

　　6. which of the following best describes the difference between event handlers and event listeners?

　　　　A：Event handler are embedded in HTML attributes;the other are assigned in JavaScript code.

　　　　B：Event handlers are a nonstandard,proprietarty browser feature;the other are standards-compliant.

　　　　C：For a given event type,an element may only have one event handler,but may have multiple event listeners.

　　　　D：IE supports event handlers;other browsers support event listeners.

　　7. Your Web page loads JavaScript code that is run using each of the following techniques:

　　　　①：DOMContentLoaded event listener　　　　　 ②：load event listener

　　　　③：