function firstpage(){
    hide();
    currpagenum = 1;
    showcurrpage(currpagenum);
    showtotalpage();
    for(i = 1; i < pagecount + 1; i++){
        blocktable.rows[i].style.display = "";
    }

    firsttext();
    pretext();
    nextlink();
    lastlink();
}

function prepage(){
    hide();
    currpagenum--;
    showcurrpage(currpagenum);
    showtotalpage();
    var firstr = firstrow(currpagenum);
    var lastr = lastrow(firstr);
    for(i = firstr; i < lastr; i++){
        blocktable.rows[i].style.display = "";
    }

    if(1 == currpagenum){
        firsttext();
        pretext();
        nextlink();
        lastlink();
    }else if(pagenum == currpagenum){
        prelink();
        firstlink();
        nexttext();
        lasttext();
    }else{
        firstlink();
        prelink();
        nextlink();
        lastlink();
    }

}

function nextpage(){
    hide();
    currpagenum++;
    showcurrpage(currpagenum);
    showtotalpage();
    var firstr = firstrow(currpagenum);
    var lastr = lastrow(firstr);
    for(i = firstr; i < lastr; i ++){
        blocktable.rows[i].style.display = "";
    }

    if(1 == currpagenum){
        firsttext();
        pretext();
        nextlink();
        lastlink();
    }else if(pagenum == currpagenum){
        prelink();
        firstlink();
        nexttext();
        lasttext();
    }else{
        firstlink();
        prelink();
        nextlink();
        lastlink();
    }
}

function lastpage(){
    hide();
    currpagenum = pagenum;
    showcurrpage(currpagenum);
    showtotalpage();
    var firstr = firstrow(currpagenum);
    for(i = firstr; i < numcount + 1; i++){
        blocktable.rows[i].style.display = "";
    }

    firstlink();
    prelink();
    nexttext();
    lasttext();
}

// 计算将要显示的页面的首行和尾行
function firstrow(currpagenum){
    return pagecount*(currpagenum - 1) + 1;
}

function lastrow(firstrow){
    var lastrow = firstrow + pagecount;
    if(lastrow > numcount + 1){
        lastrow = numcount + 1;
    }
    return lastrow;
}

function showcurrpage(cpn){
    currpagespan.innerhtml = cpn;
}

function showtotalpage(){
    pagenumspan.innerhtml = pagenum;
}

//隐藏所有行
function hide(){
    for(var i = 1; i < numcount + 1; i ++){
        blocktable.rows[i].style.display = "none";
    }
}

//控制首页等功能的显示与不显示
function firstlink(){firstspan.innerhtml = "<a href='javascript:firstpage();'  >首页</a>";}
function firsttext(){firstspan.innerhtml = "<a href='javascript:;' class='nonemaol'>首页</a>";}

function prelink(){prespan.innerhtml = "<a href='javascript:prepage();'  >上一页</a>";}
function pretext(){prespan.innerhtml = "<a href='javascript:;' class='nonemaol'>上一页</a>";}

function nextlink(){nextspan.innerhtml = "<a href='javascript:nextpage();'  >下一页</a>";}
function nexttext(){nextspan.innerhtml = "<a href='javascript:;' class='nonemaol'>下一页</a>";}

function lastlink(){lastspan.innerhtml = "<a href='javascript:lastpage();'  >尾页</a>";}
function lasttext(){lastspan.innerhtml = "<a href='javascript:;' class='nonemaol'>尾页</a>";}