Experts Exchange connects you with the people and services you need so you can get back to work.

Unable to assign a string value to an innerHTML data member in javascript

This is my JSP with html and javascript:

<div id="myPageResultContentDiv" style='display:none'>
<table id='myPageContentTable' class="content" style="width: 995px;">
                         <thead>
<tr id="0">
<th style="width: 104px;" class="active"><a id="sc0" name="sc0" href="javascript:void(0)" onClick="javascript:redoSort(0);">Serial Number</a></th>
<th style="width: 130px;" class="active"><a id="sc1" name="sc1" href="javascript:void(0)" onClick="javascript:redoSort(1);">Product Name</a></th>
<th style="width: 210px;" class="active"><a id="sc2" name="sc2" href="javascript:void(0)" onClick="javascript:redoSort(2);" class="down">Marketing Program Name</a></th>
                                    <th style="width: 210px;" class="active">Marketing Program Description</th>
<th style="width: 30px;">Remove</th>
</tr>
</thead>
                  </table>
</div>

I'm trying to populate most of the table using this line:
document.getElementById('myPageContentTable').innerHTML=strVar;

strVar is a string that contains <tr> and <td> tags that are rows that I want to insert into the table myPageContentTable using the innerHTML data member. When I try to do it the header is not showing at all in my table. Any suggestions?

jwright9Asked: 2011-02-15

Who is Participating?

LVL 14

DesignbyonyxCommented: 2011-02-15

What you are essentially doing is replacing everything inside the TABLE tag, which will replace your THEAD code. Try this:

var tBody = document.createElement("tbody");
tBody.innerHTML = strVar; // Add the rows and cells
document.getElementById('myPageContentTable').appendChild(tbody);

Open in new window

LVL 20

thehagmanCommented: 2011-02-15

... and in fact it may give cleaner code if you take the effort to populate the tBody also with DOM methods (createElement, appendChild etc.) instead of using innerHTML

LVL 14

DesignbyonyxCommented: 2011-02-15

well, I would contest that comment by saying that string concatenation and a single DOM manipulation is much faster than many DOM manipulations. Whenever possible, it is good practice to use string concatenation to build html, and use as few DOM methods as possible. Each time you call a DOM method, the DOM must be parsed and rendered by the browser. You would probably notice an application start to slow down with a couple hundred rows being added, each with 8 cells of data. That would be several thousand DOM manipulations as opposed to 1 or 2 if you use string concatenation.

You would especially notice a bog down if you were using jQuery and calling it's DOM functions one at a time. And sometimes, string concatenation is cleaner (see below)

var jsonObj = { Some JSON Object with rows of data };
var table = document.getElementById('myPageContentTable');
var tbody = document.createElement('tbody');

// --------------------------------------
// String concatenation - very fast
var tableCode = '';
for (var row in jsonObj) {
  tableCode += '<tr>';
  
  for (var cell in row) {
    tableCode += '<td>' + row[cell] + '</td>;
  }
  
  tableCode += '</tr>';
}
tbody.innerHTML = tableCode;
table.appendChild(tbody);


// --------------------------------------
// Or this, which would be much slower

for (var row in jsonObj) {
  var tr = document.createElement('tr');
  
  for (var cell in row) {
    var td = document.createElement('td');
    td.innerHTML = row[cell];
    tr.appendChild(td);
  }
  
  tbody.appendChild(tr);
}
table.appendChild(tbody);

Open in new window

LVL 20

ProculopsisCommented: 2011-02-16

Try something likr this:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<title>http://www.experts-exchange.com/Programming/Languages/Scripting/JavaScript/Q_26823698.html</title>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js" type="text/javascript"></script>
<script type="text/javascript">

jQuery(document).ready( function () {

  $("#click-me").click( function() {
    $("#myPageResultContentDiv").show();
    
    var strVar = $("#strVar").text();
    $("#myPageContentTable>thead").after( strVar );

  });

});

</script>
</head>
<body>

<input id="click-me" type="button" value="Click Me!">

<div id="myPageResultContentDiv" style='display:none'>
  <table id='myPageContentTable' class="content" style="width: 995px;">                  
    <thead>                                  
      <tr id="0">                                          
        <th style="width: 104px;" class="active"><a id="sc0" name="sc0" href="javascript:void(0)" onClick="javascript:redoSort(0);">Serial Number</a></th>
        <th style="width: 130px;" class="active"><a id="sc1" name="sc1" href="javascript:void(0)" onClick="javascript:redoSort(1);">Product Name</a></th>
        <th style="width: 210px;" class="active"><a id="sc2" name="sc2" href="javascript:void(0)" onClick="javascript:redoSort(2);" class="down">Marketing Program Name</a></th>
        <th style="width: 210px;" class="active">Marketing Program Description</th>                                    
        <th style="width: 30px;">Remove</th>
      </tr>                              
    </thead>                        
  </table>           
</div>

<fieldset style="width: 50%; padding: 20px;"><legend>Simulate <b>strVar</b> text</legend>
  <textarea id="strVar" style="width: 100%;" rows="10">

<tbody>
  <tr>
    <td>Row 1</td>
    <td>a</td>
    <td>b</td>
    <td>c</td>
    <td>d</td>
  </tr>
  <tr>
    <td>Row 2</td>
    <td>e</td>
    <td>f</td>
    <td>g</td>
    <td>h</td>
  </tr>
  <tr>
    <td>Row 4</td>
    <td>i</td>
    <td>j</td>
    <td>k</td>
    <td>l</td>
  </tr>
</tbody>

  </textarea>
</fieldset>

</body>
</html>