Programmatically change the src of an img tag

How can I change the src attribute of an img tag using javascript?

<img src="../template/edit.png" name="edit-save" alt="Edit" />

at first I have a default src which is "../template/edit.png" and I wanted to change it with "../template/save.png" onclick.

UPDATED: here's my html onclick:

<a href="#" onclick="edit()"><img src="../template/edit.png" id="edit-save" alt="Edit" /></a>

and my JS

function edit()
{   
    var inputs = document.myform;
    for(var i = 0; i < inputs.length; i++) {
        inputs[i].disabled = false;
    }
}

I've tried inserting this inside the edit(), it works but need to click the image twice

var edit_save = document.getElementById("edit-save");
    edit_save.onclick = function(){
       this.src = "../template/save.png";
    }

its ok now

function edit()
{   
    var inputs = document.myform;
    for(var i = 0; i < inputs.length; i++) {
        inputs[i].disabled = false;
    }

    var edit_save = document.getElementById("edit-save");

       edit_save.src = "../template/save.png";                              
}