document.querySelectorAll('#id').style.color = 'red'; 

function a(selector, color) {
document.querySelectorAll(selector)[].style.color = color
}
a('#a', 'red'); 

function letSomeElementChangeColor(selector, color) {
document.querySelectorAll(selector, color);
} 

function setColor(selector, color) {
xxxxxxxxxxxx
} 

document.getElementById('id').style.color = 'red';
document.getElementById('id').style.fontSize = 'px';
document.getElementById('id').style.backgourdColor = 'pink'; 

function getElement(selector) {
this.style = document.querySelecotrAll(selector).style;
}
getElement.prototype.color = function(color) {
this.style.color = color;
return this;
}
getElement.prototype.background = function(bg) {
this.style.backgroundColor = color;
return this;
}
getElement.prototype.fontSize = function(size) {
this.style.fontSize = size;
return this;
}
//调用
var el = new getElement('#id')
el.color('red').background('pink').fontSize('px'); 

document.getElementById('id').style.color = 'red';
document.getElementById('id').style.fontSize = 'px';
document.getElementById('id').style.backgourdColor = 'pink'; 

$('id').css({color:'red', fontSize:'12px', backgroundColor:'pink'}) 

//我们规定，color接受字符串类型
function setColor(color) {
if(typeof color !== 'string') return;
dosomething
} 

function fn(json) {
//为必须的参数设置默认值
var default = extend({
param: 'default',
param: 'default'
......
},json)
} 

//需要同时改变某个元素的字体和背景 
// Nightware:
function set(selector, color) {
document.querySelectroAll(selector).style.color = color;
document.querySelectroAll(selector).style.backgroundColor = color;
}
//无法扩展改函数，如果需要再次改变字体的大小的话，只能修改此函数，在函数后面填加改变字体大小的代码
//Dream
function set(selector, color) {
var el = document.querySelectroAll(selector);
el.style.color = color;
el.style.backgroundColor = color;
return el;
}
//需要设置字体、背景颜色和大小
function setAgain (selector, color, px) {
var el = set(selector, color)
el.style.fontSize = px;
return el;
} 

function sayBonjour() {
alert(this.a)
}
obj.a = ;
obj.say = sayBonjour;
obj.say();//
//or
sayBonjour.call||apply(obj);// 

function error (a) {
if(typeof a !== 'string') {
console.error('param a must be type of string')
}
}
function error() {
try {
// some code excucete here maybe throw wrong 
}catch(ex) {
console.wran(ex);
}
} 

//nighware
function set(selector, color) {
document.getElementById(selector).style.color = color;
}
//dream
zepto.init = function(selector, context) {
var dom
// If nothing given, return an empty Zepto collection
if (!selector) return zepto.Z()
// Optimize for string selectors
else if (typeof selector == 'string') {
selector = selector.trim()
// If it's a html fragment, create nodes from it
// Note: In both Chrome and Firefox , DOM error 
// is thrown if the fragment doesn't begin with <
if (selector[] == '<' && fragmentRE.test(selector))
dom = zepto.fragment(selector, RegExp.$, context), selector = null
// If there's a context, create a collection on that context first, and select
// nodes from there
else if (context !== undefined) return $(context).find(selector)
// If it's a CSS selector, use it to select nodes.
else dom = zepto.qsa(document, selector)
}
// If a function is given, call it when the DOM is ready
else if (isFunction(selector)) return $(document).ready(selector)
// If a Zepto collection is given, just return it
else if (zepto.isZ(selector)) return selector
else {
// normalize array if an array of nodes is given
if (isArray(selector)) dom = compact(selector)
// Wrap DOM nodes.
else if (isObject(selector))
dom = [selector], selector = null
// If it's a html fragment, create nodes from it
else if (fragmentRE.test(selector))
dom = zepto.fragment(selector.trim(), RegExp.$, context), selector = null
// If there's a context, create a collection on that context first, and select
// nodes from there
else if (context !== undefined) return $(context).find(selector)
// And last but no least, if it's a CSS selector, use it to select nodes.
else dom = zepto.qsa(document, selector)
}
// create a new Zepto collection from the nodes found
return zepto.Z(dom, selector)
} 

//注释接口，为了演示PPT用
function commentary() {
//如果你定义一个没有字面意义的变量时，最好为它写上注释：a：没用的变量，可以删除
var a;
//在关键和有歧义的地方写上注释，犹如画龙点睛：路由到hash界面后将所有的数据清空结束函数
return go.Navigate('hash', function(){
data.clear();
});
}