JavaScript: typeof attr.name returns undefined

Question

I am trying to get all possible data-* attributes from every tag on my page.

var el = document.body.querySelectorAll("*");
for(i=0;i<el.length;i++){
  var datas = [].filter.call(el[i].attributes, function(at) { return /^data-/.test(at.name); });
}

now datas variable contains attribute objects and I want to search datas.name for specific value, in my case I'm searching for "data-val". But typeof datas.name returns undefined. Any clue what to do? Pure JavaScript please. Thanx!

update

I could go with the following solution:

var el = document.body.querySelectorAll("*");
for(i=0;i<el.length;i++){
  var datas = [].filter.call(el[i].attributes, function(at) { return /^data-/.test(at.name); });
  for(var k=0;k<datas.length;k++){
    nodes.push(datas[k].name.replace(/^data-/,""));
  }
  for(var l=0;l<nodes.length;l++) {
    if(nodes.search("val")>0){
      ...do my code here...
    }
  }
}

but is there a more elegant way to do that?

Answer 1

var el = document.body.querySelectorAll("*"),
    i = 0,
    j = 0,
    len = el.length;

for (; i < len; i++) {
    var x = el[i].attributes,
        len2 = x.length;
    for (; j < len2; j++) {
        if (x[j].name === "data-val") console.log("data-val present");
    }
}

http://jsfiddle.net/MsSht/1/