getElementsByClassName not working
I coded a php page that displays information from a mysql database neatly into tables. I would like to hide empty table rows with an onLoad event handler.
Here is a sample table with code that hides a <td> when it has no content. but i can only get it to work with different IDs:
<script type="text/javascript">
function hideTd(id){
if(document.getElementById(id).textContent == ''){
document.getElementById(id).style.display = 'none';
}
}
</script>
</head>
<body onload="hideTd('1');hideTd('2');hideTd('3');">
<table border="1">
<tr>
<td id="1">not empty</td>
</tr>
<tr>
<td id="2"></td>
</tr>
<tr>
<td id="3"></td>
</tr>
</table>
</body>
what i want to do is use a class for the <td>s to achieve the same thing while only referencing the class once, and not referencing every single id that I want to remove, which will not even work for my dynamic content. I tried using this code:
<script type="text/javascript">
function hideTd(){
if(document.getElementsByClassName().textContent == ''){
document.getElementsByClassName().style.display = 'none';
}
}
</script>
</head>
<body onload="hideTd('1');">
<table border="1">
<tr>
<td class="1">not empty</td>
</tr>
<tr>
<td class="1"></td>
</tr>
<tr>
<td class="1"></td>
</tr>
</table>
</body>
but it does not work. its supposed to hide the empty <td>s that have the specified class. how do i hide empty <td>s using classes, not IDs?
Answer
There are several issues:
- Class names (and IDs) are not allowed to start with a digit.
- You have to pass a class to
getElementsByClassName(). - You have to iterate of the result set.
Example (untested):
<script type="text/javascript">
function hideTd(className){
var elements = document.getElementsByClassName(className);
for(var i = 0, length = elements.length; i < length; i++) {
if( elements[i].textContent == ''){
elements[i].style.display = 'none';
}
}
}
</script>
</head>
<body onload="hideTd('td');">
<table border="1">
<tr>
<td class="td">not empty</td>
</tr>
<tr>
<td class="td"></td>
</tr>
<tr>
<td class="td"></td>
</tr>
</table>
</body>
Note that getElementsByClassName() is not available up to and including IE8.
Update:
Alternatively you can give the table an ID and use:
var elements = document.getElementById('tableID').getElementsByTagName('td');
to get all td elements.
To hide the parent row, use the parentNode property of the element:
elements[i].parentNode.style.display = "none";