Javascript add item to current array
Did you mean arrayValues.push(document.getElementsByTagName('a'));?
Otherwise, you're assigning the NodeList returned by getElementsByTagName(), which overwrites the array you had just pushed values into.
Side note: there's no reason to use new Array() here. Just write var arrayValues = [];.
If you want to push all <a> elements to the array, you have to convert the NodeList to an array first. Most people use Array.prototype.slice.call(nodelist).
Once you have an array, you can then use array.push in conjunction with function.apply to push them in one call.
The resulting code looks like:
var arrayValues = [];arrayValues.push("Value 1");arrayValues.push("Value 2");arrayValues.push.apply(arrayValues, Array.prototype.slice.call(document.getElementsByTagName('a')));arrayValues.push("Value 3");