// 获取当前窗口url中param参数的值

function get_param(param){

    var query = location.search.substring(1).split('&');

    for(var i=0;i<query.length;i++){

        var kv = query[i].split('=');

        if(kv[0] == param){

            return kv[1];

        }

    }

    return null;

}

// 设置当前窗口url中param的值

function set_param(param,value){

    var query = location.search.substring(1);

    var p = new RegExp("(^|&"+param+")=[^&]*");

    if(p.test(query)){

        query = query.replace(p,"$1="+value);

        location.search = '?'+query;

    }else{

        if(query == ''){

            location.search = '?'+param+'='+value;

        }else{

            location.search = '?'+query+'&'+param+'='+value;

        }

    }

}

// 设置指定url中param的值，返回处理后的url

function set_url_param(url,param,value){

        if(url.indexOf('?') != -1){

                var p = new RegExp("(\\?|&"+param+")=[^&]*");

                if(p.test(url)){

                        url = url.replace(p,"$1="+value);

                }else{

                        url = url+'&'+param+'='+value;

                }

        }else{

                url = url+'?'+param+'='+value;

        }

        return url;

}       

// 上一页

function page_pre(current_page,page_total){

    if(parseInt(current_page) <= 1 || parseInt(current_page) > parseInt(page_total)){

        return false;

    }

    var pre_page = parseInt(current_page) - 1;

    set_param('page',pre_page);

}

// 下一页

function page_next(current_page,page_total){

    if(parseInt(current_page) < 1 || parseInt(current_page) >= parseInt(page_total)){

        return false;

    }

    var next_page = parseInt(current_page) + 1;

    set_param('page',next_page);

}