bootstrap daterangepicker汉化以及扩展功能

var selectItem = '<select id="dateranepicker_select" class="form-control width150 inline-block">';
selectItem += '今日';
selectItem += '昨日';
selectItem += '<option selected="selected">最近7日';
selectItem += '最近15日';
selectItem += '最近30日';
selectItem += '本月';
selectItem += '上月';
selectItem += '';

this.element.parent().append(selectItem);

$(document).on('change','#dateranepicker_select',function(){

function auto0(num){
return num>10?num:'0'+num;
}

var val = $(this).val();
var c_start_date = new Date();
var c_end_date = new Date();
if(val=='今日'){

}
else if(val=='昨日'){
c_start_date.setDate(c_start_date.getDate()-1);
c_end_date.setDate(c_end_date.getDate()-1);
}
else if(val=='最近7日'){
c_start_date.setDate(c_start_date.getDate()-7);
c_end_date.setDate(c_end_date.getDate()-1);
}
else if(val=='最近15日'){
c_start_date.setDate(c_start_date.getDate()-15);
c_end_date.setDate(c_end_date.getDate()-1);
}
else if(val=='最近30日'){
c_start_date.setDate(c_start_date.getDate()-30);
c_end_date.setDate(c_end_date.getDate()-1);
}
else if(val=='本月'){
var cyear = c_start_date.getFullYear();
var cmonth = c_start_date.getMonth();

c_start_date = new Date(cyear,cmonth,1);
c_end_date =new Date(cyear+'-'+ (cmonth+1) +'-'+new Date(cyear,cmonth+1,0).getDate());

}
else if(val=='上月'){
var cyear = c_start_date.getFullYear();
var cmonth = c_start_date.getMonth()-1;
c_start_date = new Date(cyear,0).getDate());
}
_this.setStartDate(c_start_date);
_this.setEndDate(c_end_date);

timespanStr =auto0(c_start_date.getMonth()+1)+'/'+ auto0(c_start_date.getDate()) + '/'+c_start_date.getFullYear()+'-'+ auto0(c_end_date.getMonth()+1) + '/' +auto0(c_end_date.getDate()) + '/' +c_end_date.getFullYear();

_this.element.val(timespanStr);
_this.hide();
_this.element.trigger('apply.daterangepicker',_this);
/ 扩展该组件 end /

});