iteration = document.getElementById("no_of_applications").value
for ( i=1;i<iteration;i++)
 {
  error_appname('application_name'+i,erSpan1)
 
 }

// Global arrays used to hold input fileds and error spans
var inputFieldArray = [];
var erSpanArray     = [];
 
 
function addRow()
{
  // Some of your code 
 
  gl.type = 'text';
  gl.name = 'application_doj' + iteration;
  gl.id = 'application_doj' + iteration;
  gl.size = 45;
  gl.className='cellData';
  gl.style.width='220px'
  gl.style.height='17px'
  gl.value='mm/dd/yyyy'
  // Removed your handlers from here and putted it below
  cellLeft.appendChild(gl);
  document.getElementById("no_of_applications").value=iteration
 
  //Adding span for showing validation error
  var erSpan = document.createElement('span');
  // Add error span to this cell.
  cellLeft.appendChild(erSpan);
 
  // Here goes ur handler
  gl.onfocus= function() {gl.value=""};
  gl.onblur= function() {ValidateForm(erSpan)}; // Passing erSpan, so that we can easily show error message 
 
  // Push elements in global arrays  
  inputFieldArray.push(gl);
  erSpanArray.push(erSpan);
 
}

function validateAll() {
  var totalRows = inputFieldArray.length; // OR erSpanArray.length
  for(var i = 0; i < totalRows; i++) {
    error_appname(inputFieldArray[i], erSpanArray[i]);
  }
}

var dgebi = document.getElementById;
// This function takes elements not elements id.
error_appname(dgebi ('application_name'+i), dgebi ('erSpan' + i));