Get the value of input text when enter key pressed

I am trying this:

<input type="text" placeholder="some text" class="search" onkeydown="search()"/>
<input type="text" placeholder="some text" class="search" onkeydown="search()"/>

with some javascript to check whether the enter key is pressed:

function search() {
    if(event.keyCode == 13) {
        alert("should get the innerHTML or text value here");
    }
}

this works fine at the moment, but my question how to get the value inside the text field, I was thinking of passing a reference "this" to the function, or if they had id's then I could use ID's but then I don't see how I could differentiate between which one has been typed, bringing my back to the same problem again...

Try this:

<input type="text" placeholder="some text" class="search" onkeydown="search(this)"/>  
<input type="text" placeholder="some text" class="search" onkeydown="search(this)"/>

JS Code

function search(ele) {
    if(event.key === 'Enter') {
        alert(ele.value);        
    }
}

DEMO Link