Javascript, alert when value is zero

I am designing a game.

There is a life point, id called ‘lifepoint’.

Also, there is a function: mouse click to decrease the value of ‘lifepoint’.

I want to have new function:

Alert when the lifepoint <= 0, my alert function is not work.

function decrementlife() {
    var element = document.getElementById('lifepoint');
    var value = element.innerHTML;

    --value;
    console.log(value);
    document.getElementById('lifepoint').innerHTML = value;
}




$(function (){
    var value = $('lifepoint').val();
    if( value  == '0' ) {
        alert('GG')
    }
})

>Solution :

Why not directly put inside the decrementlife function ?

function decrementlife() {
    var element = document.getElementById('lifepoint');
    var value = parseInt(element.innerHTML);// it's a string with innerHTML so convert to int

    --value; 
    **if(value <= 0) { alert("Boom!!")}**
    console.log(value);
    document.getElementById('lifepoint').innerHTML = value;
    
}