// 用来支持分页查询的几个函数
function firstpage()
{   
    var navform = null;
    if( document.all("gotopage")[0] )
        navform = document.all("gotopage")[0].form ;
    else
        navform = document.all("gotopage").form ;

    navform.gotopage.value=1;
    navform.submit();
}
function prevpage()
{
    var navform = null;
    if( document.all("gotopage")[0] )
        navform = document.all("gotopage")[0].form ;
    else
        navform = document.all("gotopage").form ;

    navform.gotopage.value=parseInt(navform.gotopage.value)-1;
    navform.submit();
}
function nextpage()
{
    var navform = null;
    if( document.all("gotopage")[0] )
        navform = document.all("gotopage")[0].form ;
    else
        navform = document.all("gotopage").form ;

    navform.gotopage.value=parseInt(navform.gotopage.value)+1;
    navform.submit();
}
function lastpage()
{
    var navform = null;
    if( document.all("gotopage")[0] )
        navform = document.all("gotopage")[0].form ;
    else
        navform = document.all("gotopage").form ;

    navform.gotopage.value=navform.totalpages.value;
    navform.submit();
}

// 检查是否是整数
function isInteger(value,mode)
{
  if( value == null || value.length == 0 || isNaN(value) ) return false ;

  var re = new RegExp("[^0-9\\-]");
  if( re.test(value) == true ) return false ;

  if( mode != null && mode == 1 )
    if( parseFloat(value) <=0 ) return false;
  if( mode != null && mode == 2 )
    if( parseFloat(value) <0 ) return false;

  return true ;
}

function direct_goto_page(maxpages)
{
    var navform = null;
    if( document.all("gotopage")[0] )
        navform = document.all("gotopage")[0].form ;
    else
        navform = document.all("gotopage").form ;

    if( navform.directgotopage.value != "") 
    { 
        if( !isInteger(navform.directgotopage.value) ) 
        {
            alert("Page number is not correct");
            return false;
        }
        
        var pno = parseInt(navform.directgotopage.value);
        if( pno <= 0  || pno > maxpages ) 
        {
            alert("Page number is not correct");
            return false;
        }
        
        navform.gotopage.value=navform.directgotopage.value;
        navform.submit();
    }
    
    return false;
}