手机字母索引控件

工作中写的一个手机字母索引控件，只适用于 Chrome，其它没有测试。sourcecode.zip

//矫正调用者。将 fn 作为 newObj 的方法调用

function repairCaller(newObj, fn){

    return function(){

        return fn.apply(newObj, arguments);

    }

}

function AlphaIndex( config ){

    //索引面板

    this.indexPanel = (function(){

        var alphaList = '',

            index = document.createElement('div');

        index.id = config.id;

        

        alphaList += '<li style="height:12px;" value="top">♂</li>'; 

        for(var al=65; al<=90; al++){ 

            alphaList += '<li style="height:12px;" value="' + String.fromCharCode(al) + '">' + String.fromCharCode(al) + '</li>'; 

        } 

        alphaList += '<li style="height:12px;" value="bottom">#</li>';

        

        index.innerHTML = '<ul id="' + config.id + 'Index" style="list-style:none;28px;">' + alphaList + '</ul>';

        index.style.cssText = '-webkit-padding-before:0;-webkit-padding-after:0;-webkit-margin-before:0;-webkit-margin-after:0;background:none;color:#1E2A38;font-family:\'Helvetica Neue\', HelveticaNeue, Helvetica-Neue, Helvetica, \'BBAlpha Sans\';font-size:11px;font-weight:bold;position:absolute;padding:0px;margin:0px;right:7px;top:0px;z-index:100;border-radius:12px;text-align:center;-webkit-user-select:none;overflow:hidden;';

        index.style.right = config.start.right + 'px;';

        index.style.top = config.start.top + 'px;';

        return index;

    })();

    //大号字母显示

    this.largeLetter = (function(){

        var letter = document.createElement('div');

        letter.id = config.id + "Letter";

        letter.style.cssText = 'font-family:\'Helvetica Neue\', HelveticaNeue, Helvetica-Neue, Helvetica, \'BBAlpha Sans\';color:#1E2A38;background:none;display:block;position:absolute;padding:0px;margin:0px;right:0px;top:0px;z-index:100;text-align:right;';

        letter.style.right = (config.start.right + 32)  + 'px';

        letter.style.top = config.start.top + 'px';

        letter.innerHTML = '<span style="font-size:50pt;font-weight:bold;"></span>';

        

        return letter;

    })();

    

    //保存mouseup或者鼠标移出索引框时选择的字母

    this.selectItem = null;

    

    //初始化时默认隐藏大号字母

    this.showLargeLetter = false;

    

    this.bodyScrollHeight = document.body.scrollHeight;

}

AlphaIndex.prototype.start = function(){

    //显示大写字母显示

    this.showLargeLetter = true;

    

    //绑定事件

    T.bind(document,'mousemove',repairCaller(this,this.move));

    T.bind(document,'mouseup',repairCaller(this,this.stop));

    

    //取得事件对象

    var event = T.event.getEvent(arguments[0]);

    var target = T.event.getTarget(event);

    if(target.tagName.toUpperCase() ==='LI'){

        this.selectItem = target;

        this.largeLetter.firstChild.textContent = target.textContent;

        this.largeLetter.style.top = (event.clientY + document.body.scrollTop - this.largeLetter.offsetHeight/2) + 'px';

        this.largeLetter.style.display = 'block';

    }

    this.indexPanel.style.background = '#63778F';

};

AlphaIndex.prototype.move = function(){

    //取得事件对象

    var event = T.event.getEvent(arguments[0]);

    var target = T.event.getTarget(event);

    if( target.parentNode.id == (this.indexPanel.id + 'Index') && target.tagName.toUpperCase() ==='LI'){

        this.selectItem = target;

        if(this.showLargeLetter){            

            this.largeLetter.firstChild.textContent = target.textContent;

            this.largeLetter.style.top = (event.clientY + document.body.scrollTop - this.largeLetter.offsetHeight/2) + 'px';

            this.largeLetter.style.display = 'block';

        }

    }

};

AlphaIndex.prototype.stop = function(){

    if(this.showLargeLetter && this.selectItem){

        var tc = this.selectItem.textContent;

        if(tc == '♂'){

            tc = 'top';

        }

        else if(tc == '' || tc == '#'){

            tc = 'bottom';

        }

        if(T.get(tc)){

            T.get(tc).scrollIntoView();

        }

    }

    this.showLargeLetter = false;

    this.largeLetter.style.display = 'none';

    this.indexPanel.style.background = 'none';

        

    //移除事件

    T.unbind(document,'mousemove',repairCaller(this,this.move));

    T.unbind(document,'mouseup',repairCaller(this,this.stop)); 

};

AlphaIndex.prototype.scroll = function(){

    if( (parseInt(this.indexPanel.style.top) + this.indexPanel.scrollHeight) <= this.bodyScrollHeight || document.body.scrollTop < parseInt(this.indexPanel.style.top)){

        this.indexPanel.style.top = ( (window.innerHeight - this.indexPanel.offsetHeight) > 0 ?

( (window.innerHeight - this.indexPanel.offsetHeight)/2 + document.body.scrollTop) : document.body.scrollTop )+ 'px' ;

    }

};

AlphaIndex.prototype.resize = function(){

    this.indexPanel.style.top = ( (window.innerHeight - this.indexPanel.offsetHeight) > 0 ? 

( (window.innerHeight - this.indexPanel.offsetHeight)/2 + document.body.scrollTop) : document.body.scrollTop )+ 'px' ;

};

AlphaIndex.prototype.ready = function(){

    document.body.appendChild(this.largeLetter);

    document.body.appendChild(this.indexPanel);

this.indexPanel.style.top = ( (window.innerHeight - this.indexPanel.offsetHeight) > 0 ? 

( (window.innerHeight - this.indexPanel.offsetHeight)/2 + document.body.scrollTop) : document.body.scrollTop )+ 'px' ;

    //绑定事件

    T.bind(document, 'scroll', repairCaller(this,this.scroll));

    T.bind(window, 'resize', repairCaller(this,this.resize));

    T.bind(this.indexPanel,'mousedown',repairCaller(this,this.start));

};