blur() vs. onblur()

I have a input tag with an onblur event listener:

<input id="myField" type="input" onblur="doSomething(this)" />

Via JavaScript, I want to trigger the blur event on this input so that it, in turn, calls the doSomething function.

My initial thought is to call blur:

document.getElementById('myField').blur()

But that doesn't work (though no error).

This does:

document.getElementById('myField').onblur()

Why is that? .click() will call the click event attached to an element via the onclick listener. Why does blur() not work the same way?