Edit in JSFiddle

var source = [];
for (var i = 0; i < 70000; i++) {
    source.push(i);
}

try {
    var result = source.concat.apply([], source);
    $('#result').text("result: " + result.length);
} catch(ex) {
    $('#result').text("error: " + ex);
}

<div id="result"></div>