/**

 * 获取分页按钮

 * @param total_page     总页数

 * @param current_page  当前页

 * @param num                    每页显示多少个分页按钮

 * @returns {String}

 */

function get_page_html(total_page,current_page,num){

    var page_html = "";

    if(isNaN(total_page) && isNaN(current_page)){

    }else{

        //范围判断

        if(current_page>total_page) {

            current_page = total_page;

        }

        // 当前页的前后各显示多少页

        var count = Math.floor(num/2);

        // 当前页后面要显示的页数

        var after_count = count;

        if(count-current_page>0){

            after_count += (count-current_page);

        }

        if(total_page<=1) {

            //只有一页

            page_html += '<ul class="pagination">';

            page_html += '<li class="active"><a href="javascript:pageQuery(1)">1</a></li>';

            page_html += '</ul>';

        }else if(total_page<=num){

            page_html += '<ul class="pagination">';

             //把页数全部显示出来

            for(var i=1;i<=total_page;i++) {

                if(current_page==i){

                       page_html += '<li class="active"><a href="javascript:pageQuery('+current_page+')">'+current_page+'</a></li>';

                }else{

                       page_html += '<li><a href="javascript:pageQuery('+i+')">'+i+'</a></li>';

                }

            }

            page_html += '</ul>';

        }else {

            page_html += '<ul class="pagination">';

            //显示前一页按钮

            if(current_page-count>1) {

                page_html += '<li><a href="javascript:pageQuery('+(current_page-1)+')">&laquo;</a></li>';

            }

            //显示当前页前面的页码按钮

            for(var i=count;i>=1;i--) {

                if(current_page-i>0){

                    page_html += '<li><a href="javascript:pageQuery('+(current_page-i)+')">'+(current_page-i)+'</a></li>';

                }

            }

            // 当前页按钮

            page_html += '<li class="active"><a href="javascript:pageQuery('+current_page+')">'+current_page+'</a></li>';

            // 显示当前页后面的页码按钮

            for(var j=1;j<=after_count;j++){

                if((current_page+j)<=total_page){

                    page_html += '<li><a href="javascript:pageQuery('+(current_page+j)+')">'+(current_page+j)+'</a></li>';

                }

            }

            //显示后一页按钮

            if(current_page+count<total_page){

                page_html += '<li><a href="javascript:pageQuery('+(current_page+1)+')">&raquo;</a></li>';

            }

            page_html += '</ul>';

        }

    }

    return page_html;

}