Output disappeared Javascript simple innerHTML

Question

I am new to javascript and on every simple thing i get some kind of problem but this seems un-solve-able to me. I googled and nothing simillar.

After i input data into textbox and store it into variable, i print out variable in paragraph. Problem is that output i printed out disappears within less than second. Code seems to be normal, what might it be? It looks like c when you dont put getch(); Thanks in advance.

<form>Unesite broj koji ce se ispisat kasnije.<br>
<input type="text" id="userInput">
<input type="submit" name="unos" value="Unesi i ispisi" onclick="unesi()"><br><br>

</form> 
    <br><br>
<p>Unjeli ste <b id="ispis"></b></p>
<script>
function unesi(){
var userInput = document.getElementById('userInput').value;
document.getElementById('ispis').innerHTML = userInput;
}   

</script>

Answer 1

The <form> tag doesn't specify an action attribute, so when you click the submit button, the browser will submit the form to the current URL - which will look a lot like the page is refreshing.

If you want to run the unesi function when the user clicks submit and prevent the HTML form from submitting, you need to change it slightly:

<input type="submit" name="unos" value="Unesi i ispisi"
      onclick="unesi(); return false;">

The return false prevents the form from submitting itself.