Question

I have function which has parameter itself and it is working fine

javascript//

<script type="text/javascript">
function $(id){
    document.getElementById(id).style.color="#ff0000"
}
</script>

HTML//

<a href="#" onclick="$('me')">click me</a>
<div id="me">color</div>

Now I change this function a little bit which is not working
javascript//

<script type="text/javascript">
function $(id){

    document.getElementById(id)
}

function aaa(){

    $('me').style.color="#ff0000"

}
</script>

HTML//

<a href="#" onclick="aaa()">click me</a>
<div id="me">color</div>

why this function working without return statement

<script type="text/javascript">
function $(id){

    alert(id)
}

function aaa(){

    $('me')

}
</script>

Answer 1

Your function $(id) does not return anything. It should return the element that you are finding:

<script type="text/javascript">

function $(id){
    return document.getElementById(id);
}

function aaa(){    
    $('me').style.color="#ff0000";
}
</script>

PS. You should probably refrain from naming your function $.