邮箱的广泛使用得益于它的免费，因此很多网站在注册的时候都会直接使用邮箱作为账号名
为了提高用户的体验，很多网站都会实现邮箱输入的自动提示功能，所有自己也实现了一个，先看下效果吧，觉得效果还行的就拿去

核心代码（需要jquery的支持）：

(function($){ $.fn.mailAutoComplete = function(options){ var defaults = { boxClass: "mailListBox", //外部box样式 listClass: "mailListDefault", //默认的列表样式 focusClass: "mailListFocus", //列表选样式中 markCalss: "mailListHlignt", //高亮样式 zIndex: 1, autoClass: true, //是否使用插件自带class样式 mailArr: ["qq.com","gmail.com","126.com","163.com","hotmail.com","yahoo.com","yahoo.com.cn","live.com","sohu.com","sina.com"], //邮件数组 textHint: false, //文字提示的自动显示与隐藏 hintText: "", focusColor: "#333" //blurColor: "#999" }; var settings = $.extend({}, defaults, options || {}); //页面装载CSS样式 if(settings.autoClass && $("#mailListAppendCss").size() === 0){ $('<style id="mailListAppendCss" type="text/css">.mailListBox{border:1px solid #369; background:#fff; font:12px/20px Arial;}.mailListDefault{padding:0 5px;cursor:pointer;white-space:nowrap;}.mailListFocus{padding:0 5px;cursor:pointer;white-space:nowrap;background:#369;color:white;}.mailListHlignt{color:red;}.mailListFocus .mailListHlignt{color:#fff;}</style>').appendTo($("head")); } var cb = settings.boxClass, cl = settings.listClass, cf = settings.focusClass, cm = settings.markCalss; //插件的class变量 var z = settings.zIndex, newArr = mailArr = settings.mailArr, hint = settings.textHint, text = settings.hintText, fc = settings.focusColor, bc = settings.blurColor; //创建邮件内部列表内容 $.createHtml = function(str, arr, cur){ var mailHtml = ""; if($.isArray(arr)){ $.each(arr, function(i, n){ if(i === cur){ mailHtml += '<div class="mailHover '+cf+'" id="mailList_'+i+'"><span class="'+cm+'">'+str+'</span>@'+arr[i]+'</div>'; }else{ mailHtml += '<div class="mailHover '+cl+'" id="mailList_'+i+'"><span class="'+cm+'">'+str+'</span>@'+arr[i]+'</div>'; } }); } return mailHtml; }; //一些全局变量 var index = -1, s; $(this).each(function(){ var that = $(this), i = $(".justForJs").size(); if(i > 0){ //只绑定一个文本框 return; } var w = that.outerWidth(), h = that.outerHeight(); //获取当前对象（即文本框）的宽高 //样式的初始化 that.wrap('<span style="display:inline-block;position:relative;"></span>') .before('<div id="mailListBox_'+i+'" class="justForJs '+cb+'" style="min-width:'+w+'px;_width:'+w+'px;position:absolute;left:-6000px;top:'+h+'px;z-index:'+z+';"></div>'); var x = $("#mailListBox_" + i), liveValue; //列表框对象 that.focus(function(){ //父标签的层级 $(this).css("color", fc).parent().css("z-index", z); //提示文字的显示与隐藏 if(hint && text){ var focus_v = $.trim($(this).val()); if(focus_v === text){ $(this).val(""); } } //键盘事件 $(this).keyup(function(e){ s = v = $.trim($(this).val()); if(/@/.test(v)){ s = v.replace(/@.*/, ""); } if(v.length > 0){ //如果按键是上下键 if(e.keyCode === 38){ //向上 if(index <= 0){ index = newArr.length; } index--; }else if(e.keyCode === 40){ //向下 if(index >= newArr.length - 1){ index = -1; } index++; }else if(e.keyCode === 13){ //回车 if(index > -1 && index < newArr.length){ //如果当前有激活列表 $(this).val($("#mailList_"+index).text()); } }else{ if(/@/.test(v)){ index = -1; //获得@后面的值 //s = v.replace(/@.*/, ""); //创建新匹配数组 var site = v.replace(/.*@/, ""); newArr = $.map(mailArr, function(n){ var reg = new RegExp(site); if(reg.test(n)){ return n; } }); }else{ newArr = mailArr; } } x.html($.createHtml(s, newArr, index)).css("left", 0); if(e.keyCode === 13){ //回车 if(index > -1 && index < newArr.length){ //如果当前有激活列表 x.css("left", "-6000px"); } } }else{ x.css("left", "-6000px"); } }).blur(function(){ if(hint && text){ var blur_v = $.trim($(this).val()); if(blur_v === ""){ $(this).val(text); } } $(this).css("color", bc).unbind("keyup").parent().css("z-index",0); x.css("left", "-6000px"); }); //鼠标经过列表项事件 //鼠标经过 $(".mailHover").live("mouseover", function(){ index = Number($(this).attr("id").split("_")[1]); liveValue = $("#mailList_"+index).text(); x.children("." + cf).removeClass(cf).addClass(cl); $(this).addClass(cf).removeClass(cl); }); }); x.bind("mousedown", function(){ that.val(liveValue); }); }); }; })(jQuery);

页面（这里就取一个div做实例）：

<div class="reg_lin1"><div class="lin1_1">常用邮箱：</div><div class="lin1_2"><input type="text" class = "reg_text" id = "email" name = "email"/></div><div class="lin1_3"></div></div><script type="text/javascript">$("#email").mailAutoComplete({boxClass: "out_box", //外部box样式listClass: "list_box", //默认的列表样式focusClass: "focus_box", //列表选样式中markCalss: "mark_box", //高亮样式autoClass: false,textHint: true //提示文字自动隐藏});</script>

还有点css，这个可能需要大家自己修改成自己想要的色调

<!-- 邮箱自动提示的css --> <style type="text/css"> .out_box{border:1px solid #ccc; background:#fff; font:12px/20px Tahoma;} .list_box{border-bottom:1px solid #eee; padding:0 5px; cursor:pointer;} .focus_box{background:#f0f3f9;} .mark_box{color:#c00;} </style>

以上就是jquery实现邮箱自动填充提示功能的全部代码，希望对大家的学习有所帮助。