Referencing DOM elements in IE11 vs IE8

Question

I have a website that contains the following HTML/javascript:

<input type="text" id="txtPhaseID" onkeypress="return onlyNumbers();" />
<a id="btnLookup" onclick="GetEventLookupData(txtPhaseID.value);this.blur();return false;" href="javascript:void(0);" class="btn"><span>Lookup</span></a>

The reference to txtPhaseID.value in the onclick event works in IE8 but fails in IE11. I'd expect it to fail in both since you should have to use document.getElementById.

Why does this work in IE8?

Answer 1

Technically when you add an id to an element you could access it directly from the DOM with id.property - but it's always been considered very bad practice to a point that no one was ever taught that way. I can only imagine it was finally removed in Internet Explorer 11. I have no idea what this is called and I don't think it's ever been given a specific name, which means Googling will return pretty limited results. Unfortunately, if they did remove it there probably isn't anything saying so.

Here are some other resources from stackoverflow for more information:

Do DOM tree elements with ids become global variables?

Why don't we just use element IDs as identifiers in JavaScript?