Detailed explanation of examples of paged viewing of images

<table height="120" border="0" align="center" cellpadding="5" cellspacing="0"> 
          <script language="javascript" type="text/javascript"> 
function int(I,k) 
{ 
//define variable 
var ff=0; 
var j; 
j=Math.round(I/k)-I/k; 
if (j!=0){ 
ff=Math.round(I/k)+1;} 
else 
{ 
ff=Math.round(I/k); 
} 
return ff; 
} 
function querystring(qs){ 
s=location.href; 
s=s.replace("?","?&").split("&"); 
re=""; 
for(i=1;i<s.length;i++){ 
if(s[i].indexOf(qs+"=")==0){ 
  re=s[i].replace(qs+"=",""); 
  } 
} 
  return re; 
} 
         var page=querystring("page") 
         if(page==false){ 
page=1 
} 
          var maxperpage=4 //每页显示条数，这里每页显示4张 
                  var totalimg=8 //一共有多少张图片这里共8张 
                  var filename="list.htm" //这个文件的名称 
                  var pagecounts 
          var cnum,snum,onum,endnum,kstr 
          var startnum=((page-1)*maxperpage); 
          endnum=startnum+maxperpage; 
          var x=0; 
                  pagecounts=int(totalimg,maxperpage) 
          if(page==pagecounts){ 
          endnum=((pagecounts-1)*maxperpage)+totalimg-(pagecounts-1)*maxperpage 
          } 
          for(k=startnum+1;k<=endnum;k++){ 
         kstr=k.toString(); 
         if(k<10){ 
         kstr="00"+kstr 
         } 
         else 
         { 
         kstr="0"+kstr 
         } 
          x+=1; 
          //显示数据 
          if(x%2==0){ 
          document.write("<td><img src=img/LX-"+kstr+".jpg width=230 height=290 onclick=javascrpt:window.open(this.src) style=&#39;cursor:hand&#39;></td></tr>"); 
          }else{ 
          document.write("<tr><td><img src=img/LX-"+kstr+".jpg width=230 height=290 onclick=javascrpt:window.open(this.src) style=&#39;cursor:hand&#39;></td>"); 
          } 
          } 
          </script> 
            </table><table width="100%" height="23" border="0" cellpadding="0" cellspacing="0"> 
  <tr> 
    <td><label> 
      <p align=center><span id="dinfo"></span><select name="select" onChange="location.href=this.options[this.selectedIndex].value"> 
        <script type="text/javascript" language="javascript"> 
document.getElementById("dinfo").innerHTML="共有<font color=red>"+totalimg.toString()+"</font>条记录 共<font color=red>"+pagecounts+"</font>页 每页<font color=red>"+maxperpage+"</font>条 "; 
        for(y=1;y<=pagecounts;y++){ 
        if(page==y){ 
        document.write("<option value="+filename+"?page="+y+" selected>"+y+"</option>"); 
        }else{ 
        document.write("<option value="+filename+"?page="+y+">"+y+"</option>"); 
        } 
        } 
        </script> 
        </select></p> 
    </label></td> 
  </tr> 
</table>