SO fiddle

Test Fiddle mainly for SO Questions

by Nick Craver

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/overcast/jquery-ui.css">
<div id="elm0" data-color="color" data-size="size" data-more="more">something</div>
<div id="elm1">This element must get elem0 attr</div>

JavaScript

var elm0a = document.getElementById("elm0").attributes,
    elm1 = document.getElementById("elm1");
for(var i=0; i<elm0a.length; i++) {
    var a = elm0a[i];
    if(a.name.indexOf("data-") == 0)
        elm1.setAttribute(a.name, a.value);
}
alert($("#elm1").attr("data-more"));