javascript - Why doesn't getElementByClassName -> getElementsByTagName -> setAttribute work? - Stack Overf

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I want open certain links in a new tab. Since I can't set it directly into the <a> tag, I want to put the link into <span> tags with a certain class name and set the target attribute via JavaScript.

I thought this would be easy, but I can't get it working:

addOnloadHook(function () {
  document.getElementByClassName('newTab').getElementsByTagName('a').setAttribute('target', '_blank');
});

<span class="newTab"><a href="">Link</a></span>

What am I doing wrong?

I want open certain links in a new tab. Since I can't set it directly into the <a> tag, I want to put the link into <span> tags with a certain class name and set the target attribute via JavaScript.

I thought this would be easy, but I can't get it working:

addOnloadHook(function () {
  document.getElementByClassName('newTab').getElementsByTagName('a').setAttribute('target', '_blank');
});

<span class="newTab"><a href="http://www.">Link</a></span>

What am I doing wrong?

• javascript
• getelementsbytagname
• getelementsbyclassname
• setattribute

Share Improve this question Follow edited Mar 16, 2015 at 18:45 Ben 10.1k55 gold badges4242 silver badges4242 bronze badges asked Sep 26, 2010 at 12:53 MartinMartin 2,02766 gold badges2828 silver badges4444 bronze badges

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2 Answers 2

Sorted by: Reset to default 8

document.getElementByClassName does not exist, the correct function is document.getElementsByClassName (note the extra s). It returns an array of matching nodes, so you've to give an index:

addOnloadHook(function () {
  document.getElementsByClassName('newTab')[0].getElementsByTagName('a')[0].setAttribute('target', '_blank');
});

but you might need to iterate through every span with the specified class ('newTab') on the page for it to work:

addOnLoadHook(function(){

  var span = document.getElementsByClassName('newTab');

  for(var i in span) {
    span[i].getElementsByTagName('a')[0].setAttribute('target','_blank');
  }

});

in case you'll have more than 1 anchor tag in a span you'd also have to iterate through the anchor tags like this:

addOnLoadHook(function(){

  var span = document.getElementsByClassName('newTab');

  for(var i in span){
    var a = span[i].getElementsByTagName('a');
    for(var ii in a){
      a[ii].setAttribute('target','_blank');
    }
  }

});

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