How to get all elements which name starts with some string?

I have an HTML page. I would like to extract all elements whose name starts with "q1_".

How can I achieve this in JavaScript?


A quick and easy way is to use jQuery and do this:

var $eles = $(":input[name^='q1_']").css("color","yellow");

That will grab all elements whose name attribute starts with 'q1_'. To convert the resulting collection of jQuery objects to a DOM collection, do this:

var DOMeles = $eles.get();

see http://api.jquery.com/attribute-starts-with-selector/

In pure DOM, you could use getElementsByTagName to grab all input elements, and loop through the resulting array. Elements with name starting with 'q1_' get pushed to another array:

var eles = [];
var inputs = document.getElementsByTagName("input");
for(var i = 0; i < inputs.length; i++) {
    if(inputs[i].name.indexOf('q1_') == 0) {
        eles.push(inputs[i]);
    }
}

You can use getElementsByName("input") to get a collection of all the inputs on the page. Then loop through the collection, checking the name on the way. Something like this:

<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>JS Bin</title>

</head>
<body>

  <input name="q1_a" type="text" value="1A"/>
  <input name="q1_b" type="text" value="1B"/>
  <input name="q1_c" type="text" value="1C"/>
  <input name="q2_d" type="text" value="2D"/>

  <script type="text/javascript">
  var inputs = document.getElementsByTagName("input");
  for (x = 0 ; x < inputs.length ; x++){
    myname = inputs[x].getAttribute("name");
    if(myname.indexOf("q1_")==0){
      alert(myname);
      // do more stuff here
       }
    }
    </script>
</body>
</html>

Demo