@DBColumn and @DBLookup for all browsers using Ajax

• Rishikesh Sahi
• Published: 19 Sep 2005

This generic code can be used to perform @DBColumn and @DBLookup using Ajax (Asynchronous JavaScript and XML) in all browsers. It's perfectly tested on Mozilla, Netscape and of course Internet Explorer. And it's easy to use without changing any line from the code.

var req;
var attr
var xmlkey;
var resultColXML= new Array()
var resultlkpXML= new Array()
var ObjCombo1;
var ObjCombo2;
var lkpKey;

/*--------------------------- 
Dbcolumn function start here 
-------------------*/

function dbColumn
(server,path,view,column,Subject) 
{
 ObjCombo1=Subject   
//Put your first combo name 
here to get dbcolumn result
 var pos=0;
 currURL = 
(document.location.href).toLowerCase();
 
   if (trim(server) == "")
  {
  pos = currURL.indexOf('://'); 
  if (pos < 0 )
   server = "http://10.50.3.107" 
// Put your server name here 
  else
  {
   pos += 3;
   pos = currURL.indexOf('/', pos);
   server = currURL.substring(0, pos)
   alert(server)
  }
   }

  if( trim(path) == "" )
  {
   if( pos > 0 )
   {
    newPos = currURL.indexOf('.nsf',pos);
    if (newPos > 0)
    {
path = currURL.substring
(pos+1,newPos+4)
    }
   }
    }

  if( !isNaN(column) )
  column -= 1; 
  
vurl = trim(server)+"/"+
trim(path)+"/"+view+"?Readviewentries"

//checking whether browser is 
Mozila or Netscape
if (window.XMLHttpRequest) 
 {
req = new XMLHttpRequest();
req.overrideMimeType('text/xml');
req.onreadystatechange = 
processReqChange_Col;
req.open("GET", vurl , true);
req.send(null);
      } 
//checking whether browser is IE 
else if (window.ActiveXObject)
{
 
req = new ActiveXObject("Microsoft.XMLHTTP");
if (req)
{
req.onreadystatechange = 
processReqChange_Col;
req.open("GET", vurl, true);
req.send();
           }
        }
}


/* Function used to check whether 
XML file loaded completely or not */

function processReqChange_Col() 
{
if (req.readyState == 4)         
/*Only process if XML
 file is loaded completely:4="Complete" */
  {
         if (req.status == 200)        
\/*Only process if everything is ok*/
    {
response  = req.responseXML.
documentElement;
populateColumn(response)
        } 
    else 
   {
alert("There was a problem 
retrieving he XML data:n" + req.statusText);
           }
       }
}

/* Function used to extract 
value one by one from XML file */

function populateColumn(responseXML)
{
NodeList = 
responseXML.getElementsByTagName
("viewentry") 

for (var k=0;k&ltNodeList.lengthk+=1)
 {
child = 
responseXML.getElementsByTagName
('text')[k].firstChild
 
 while (child != null)
  { 
filterNode = 
responseXML.getElementsByTagName
("viewentry") 
var filterItem = filterNode.item(k); 
posNumber = filterItem.getAttribute("position"); 
     
if (( child.nodeType == 3) && 
(posNumber.indexOf(".")==-1)) 
{  
resultColXML[k] = trim(child.nodeValue);
           } 
           child = child.nextSibling 
       }   
     }
      var finalresult= new Array()
      var tmpstr="";
      var sep="";

 for (var p=0;p&ltresultColXML.lengthp++)
  {
   if (resultColXML[p] != '' && resultColXML[p] != null )
   {
    tmpstr =tmpstr+sep+trim(resultColXML[p])
    sep="#"
   } 
  }
  finalresult = tmpstr.split("#")
  writeInCombo(finalresult,ObjCombo1)
}

/* Function used to trim string */

function trim(str)
{
  return str.replace(/^s+/g, '').replace(/s+$/g, '');
} 

/*--------------------------- 
writing in combo function start here
 -------------------*/

function writeInCombo(data,fldCombo)
{
 fldCombo.length=0
 fldCombo.length +=1
 fldCombo[fldCombo.length-1].text = "--Select--"
 for(iCount=0;iCount&ltdata.lengthiCount++)
 {
  fldCombo.length +=1
  strText=data[iCount]  
  if (strText !=undefined && strText != null)
  { 
   fldCombo[fldCombo.length-1].text = trim(strText) 
  }
 } 
 
}

/*--------------------------- 
Dblookup function start here
 -------------------*/

function dbLookup(server,path,view,key,column,Name)
{
 lkpKey=key
 ObjCombo2=Name  
//Put your second combo name 
here to get dblookup result
 var pos=0;
 currURL = (document.location.href).toLowerCase();
 
   if (trim(server) == "")
  {
  pos = currURL.indexOf('://'); 
  if (pos < 0 )
   server = "http://10.50.3.107"  
// Put your server name here
  else
  {
   pos += 3;
   pos = currURL.indexOf('/', pos);
   server = currURL.substring(0, pos)
   alert(server)
  }
   }

  if( trim(path) == "" )
  {
   if( pos > 0 )
   {
    newPos = currURL.indexOf('.nsf',pos);
    if (newPos > 0)
    {
     path = currURL.substring(pos+1,newPos+4)
    }
   }
    }

  if( !isNaN(column) )
  column -= 1; 
  
vurl = trim(server)+"/"+trim(path)+"/"+view+"?
Readviewentries&restricttocategory="+lkpKey
    
//checking whether browser is mozila or Netscape
if (window.XMLHttpRequest) 
 {
req = new XMLHttpRequest();
req.overrideMimeType('text/xml');
req.onreadystatechange = 
processReqChange_lookup;
req.open("GET", vurl , true);
req.send(null);
      } 
        //checking whether browser is IE 
 else if (window.ActiveXObject)
  {
 
req = new ActiveXObject("Microsoft.XMLHTTP");
 if (req)
   {
req.onreadystatechange = 
processReqChange_lookup;
req.open("GET", vurl, true);
req.send();
           }
        } 
}


/* Function used to check whether 
XML file loaded completely or not */

function processReqChange_lookup() 
{
    if (req.readyState == 4)             
 /*Only process if XML 
file is loaded completely:4="Complete" */
  {
         if (req.status == 200)           
 /*Only process if everything is ok*/
    {
response  = req.responseXML.documentElement;   
populatelookup(response)
        } 
    else 
   {
alert("There was a problem retrieving 
the XML data:n" + req.statusText);
          }
       }
}

/* Function used to extract
 value one by one from XML file */

function populatelookup(responseXML)
{
 NodeList = 
responseXML.getElementsByTagName("viewentry") 
     var tmplkpstr="";
     var sep="";
     
 for(var i=0; i&ltNodeList.length i++)
 {
  tmplkpstr = 
tmplkpstr+sep+NodeList[i].getElementsByTagName
("text")[0].childNodes[0].nodeValue
  sep="#"
  } 
  finallkpresult = tmplkpstr.split("#")
  writeInCombo(finallkpresult,ObjCombo2)  
  
}

Steps to use:

1. Make your first column categarized in view (which you wana use for dbcolumn and dblookup).
2. Assume you have to combo on form. So, call function Dbcolumn on OnLoad of the form:

   ObjCombo1=document.forms[0].Combo1;
   ObjCombo2=document.forms[0].Combo2;
   dbColumn("serverName",
   "DbName",viewname,1,Combo1)
   

3. When you select any option from combo1 then its respective value should come in second combo. So, call dblookup function on OnChange of first combo:

   keyVal=ObjCombo1.options
   [ObjCombo1.selectedIndex].text;
   ObjCombo2.length=0
   dbLookup("ServerName","DBName",
   viewname,keyVal,2,ObjCombo2)
   

The last parameter in both functions is comboBox name object, which is on your form used to display options.

vurl = trim(server)+"/"+trim(path)+"/"+
view+"?Readviewentries" 
    vurl = trim(server)+"/"+trim(path)+"/"+
view+"?Readviewentries&
restricttocategory="+lkpKey

vurl = "/"+trim(path)+"/"+view+"?
Readviewentries" 
    vurl = "/"+trim(path)+"/"+view+"?
Readviewentries&restricttocategory="+lkpKey

function populatelookup(responseXML)
{
NodeList = 
responseXML.getElementsByTagName
("viewentry") 
    var tmplkpstr="";
    var sep="";
    
for(var i=0; i<NodeList.length; i++)
{
 tmplkpstr = 
tmplkpstr+sep+NodeList[i].
getElementsByTagName
("text")[0].childNodes[0].nodeValue
 sep="#"
 ] 
 finallkpresult = tmplkpstr.split("#")
 writeInCombo(finallkpresult,ObjCombo2)
 
 
]

function populatelookup(responseXML) 
{ 
NodeList = responseXML.
getElementsByTagName("viewentry") 
var tmplkpstr=""; 
var sep="";         
var multiNodeListNbr; 
          
for(var i=0; i<NodeList.length; i++) { 
// is this a multivalue list, then the 
statement below will equal greater than 1         
multiNodeListNbr        
 = NodeList[0].
getElementsByTagName("text").length; 
if (NodeList[0].
getElementsByTagName("text").length == 1) { 
tmplkpstr = tmplkpstr+sep+NodeList[i].
getElementsByTagName
("text")[0].childNodes[0].nodeValue; 
sep="#"                           
] else {                 
 // interate through all the list entrie
for (var z = 0; z <multiNodeListNbr; z++) { 
tmplkpstr = tmplkpstr+sep+
NodeList[0].getElementsByTagName
("textlist")[0].getElementsByTagName
("text").item(z).firstChild.data; sep="#"
] 
] 
] 

finallkpresult = tmplkpstr.split("#") 
writeInCombo(finallkpresult,ObjCombo2) 
]