jquery 实现邮箱输入自动提示功能

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>