var get=document.getElementById("nameholder").value;
var submit=document.getElementById("submit");
submit.addEventListener("click",function(){
console.log(get);
});
Try this below:
var submit = document.getElementById("submit");
submit.addEventListener("click", function() {
var get = document.getElementById("nameholder").value;
console.log(get);
});<input type='text' id="nameholder" />
<input type='submit' id="submit" />