分享我對JS插件開發的一些感想和心得_javascript技巧

<div class="pager">
<span class="flip noPage">上一页</span>
<span class="curPage">1</span>
<a page="1" href="javascript:;">2</a>
<a page="2" href="javascript:;">3</a>
<a page="3" href="javascript:;">4</a>
<span>...</span> 
<a href="javascript:;" page="8">9</a> 
<a page="1" href="javascript:;" class="flip">下一页</a>
</div> 

.pager { display: inline-block; font: 12 px/21px "宋体"; margin-top: 20px; }
.pager a, .pager .flip, .pager .curPage { border: 1px solid #e3e3e3; display: inline-block; height: 22px; line-height: 22px; text-align: center; }
.pager a { background: none repeat scroll 0 0 #fff; color: #010101; text-decoration: none; width: 26px; }
.pager a:hover { background: none repeat scroll 0 0 #f1f1f1; }
.pager .noPage { color: #a4a4a4; }
.pager .curPage { background: none repeat scroll 0 0 #49abde; color: #ffffff; width: 26px; }
.pager .flip { width: 56px; } 

; (function ($, window, document, undefined) {
"use strict";
var defaults = {
pageIndex: 0,
pageSize: 6,
itemCount: 50,
maxButtonCount: 7,
prevText: "上一页",
nextText: "下一页",
buildPageUrl: null,
onPageChanged: null
}; 
$.fn.pager = function (options) {
options = $.extend(defaults, options || {});
}
})(jQuery, window, document); 

; (function ($, window, document, undefined) {
"use strict";
var defaults = {
pageIndex: 0,
pageSize: 6,
itemCount: 50,
maxButtonCount: 7,
prevText: "上一页",
nextText: "下一页",
buildPageUrl: null,
onPageChanged: null
};
function Pager($ele, options) {
this.$ele = $ele;
this.options = options = $.extend(defaults, options || {});
this.init();
}
Pager.prototype = {
constructor: Pager,
init: function () {
this.renderHtml();
this.bindEvent();
},
renderHtml: function () {
var options = this.options;
options.pageCount = Math.ceil(options.itemCount / options.pageSize);
var html = [];
//生成上一页的按钮
if (options.pageIndex > 0) {
html.push('<a page="' + (options.pageIndex - 1) + '" href="' + this.buildPageUrl(options.pageIndex + 1) + '" class="flip">' + options.prevText + '</a>');
} else {
html.push('<span class="flip noPage">' + options.prevText + '</span>');
}
//这里是关键
//临时的起始页码中间页码，当页码数量大于显示的最大按钮数时使用
var tempStartIndex = options.pageIndex - Math.floor(options.maxButtonCount / 2) + 1;
//计算终止页码，通过max计算一排按钮中的第一个按钮的页码，然后计算出页数量
var endIndex = Math.min(options.pageCount, Math.max(0, tempStartIndex) + options.maxButtonCount) - 1;
var startIndex = Math.max(0, endIndex - options.maxButtonCount + 1);
// 第一页
if (startIndex > 0) {
html.push("<a href='" + this.buildPageUrl(0) + "' page='" + 0 + "'>1</a> ");
html.push("<span>...</span>");
}
//生成页码按钮
for (var i = startIndex; i <= endIndex; i++) {
if (options.pageIndex == i) {
html.push('<span class="curPage">' + (i + 1) + '</span>');
} else {
html.push('<a page="' + i + '" href="' + this.buildPageUrl(options.pageIndex + 1) + '">' + (i + 1) + '</a>');
}
}
// 最后一页
if (endIndex < options.pageCount - 1) {
html.push("<span>...</span> ");
html.push("<a href='" + this.buildPageUrl(options.pageCount - 1) + "' page='" + (options.pageCount - 1) + "'>" + options.pageCount + "</a> ");
}
//生成下一页的按钮
if (options.pageIndex < options.pageCount - 1) {
html.push('<a page="' + (options.pageIndex + 1) + '" href="' + this.buildPageUrl(options.pageIndex + 1) + '" class="flip">' + options.nextText + '</a>');
} else {
html.push('<span class="flip noPage">' + options.nextText + '</span>');
}
this.$ele.html(html.join(""));
},
bindEvent: function () {
var that = this;
that.$ele.on("click", "a", function () {
that.options.pageIndex = parseInt($(this).attr("page"), 10);
that.renderHtml();
that.options.onPageChanged && that.options.onPageChange(that.options.pageIndex);
})
},
buildPageUrl: function () {
if ($.isFunction(this.options.buildPageUrl)) {
return this.options.buildPageUrl(pageIndex);
}
return "javascript:;";
} 
};
$.fn.pager = function (options) {
options = $.extend(defaults, options || {});
return new Pager($(this), options);
}
})(jQuery, window, document); 

getPageIndex: function () {
return this.options.pageIndex;
},
setPageIndex: function (pageIndex) {
this.options.pageIndex = pageIndex;
this.renderHtml();
},
setItemCount: function (itemCount) {
this.options.pageIndex = 0;
this.options.itemCount = itemCount;
this.renderHtml();
}