<button onclick="test()">Button 1</button>
<button onclick="test()">Button 2</button>
<button onclick="test()">Button 3</button>

function test()
{
    var button_name = this.html;
    console.log("Im button "+ button_name);
}

<button onclick="test(this)">Button 1</button>

function test(elem){
   var button_name = elem.textContent;
}

<button onclick="test(this)">Button 1</button>

var buttons = document.querySelectorAll("selector-for-the-buttons");
Array.prototype.forEach.call(buttons, function(btn) {
    btn.addEventListener("click", handler, false);
});
function handler() {
    // Use `this` here
}

$("selector-for-the-buttons").on("click", function() {
    // Use `this` here
});

document.querySelector("selector-for-the-container").addEventListener("click", function(e) {
    // Use `e.target` here
}, false);

$("selector-for-the-container").on("click", "button", function() {
    // Use `this` here (note this is different from the DOM version above)
});

<button onclick="test(this)">1</button>
<button onclick="test(this)">2</button>
<button onclick="test(this)">3</button>

<script>
    function test(t)
    {
        console.log(t);
    }
</script>

<button onclick="test(this)">1</button>
<button onclick="test(this)">2</button>
<button onclick="test(this)">3</button>

<script>
   function test(button)
   {
       var button_name = $(button).html();
       alert("Im button "+ button_name);
   }
</script>

<button onclick="test(this.id)" id="button1">1</button>
<button onclick="test(this.id)" id="button2">2</button>
<button onclick="test(this.id)" id="button3">3</button>

<script>
    function test(id)
    {
        var button_name = id;
        alert("Im button name is : "+ button_name);
        console.log("Im button name is :"+ button_name);
    }
</script>