Getting an anchor value which is inside a li tag
<li class="email">
    <a href="mailto:abc@gmail.com">abc@gmail.com</a>
</li>

var elem = document.querySelectorAll('.email');
var email = elem[0].children[0].innerHTML;

var elems = document.querySelectorAll('.email');
for(var i = 0; i < elems.length; i++) {
    var elem = elems[i];
    console.log(elem.firstElementChild.getAttribute('href').substr(7));
}

[].forEach.call( document.getElementsByClassName( 'email' ), function( el ) {
    console.log( el.firstElementChild.textContent );
} );

function getElsByClassName(classname){
    var rv = [];
    var elems  = document.getElementsByTagName('*')
    if (elems.length){
        for (var x in elems ){
            if (elems[x] && elems[x].className && elems[x].className == classname){
                rv.push(elems[x]);
            }
        }
    }
    return rv;
}

//Get the li
var li = getElsByClassName("email"); //Alass, it returns an array
var a = li[0].firstChild;
var email = a.getAttribute('href').substr(7);

var email=document.getElementsByClassName('email')[0].getElementsByTagName('a')[0];

alert(email.innerHTML); // will print abc@gmail.com