Question

I’ve come across a very bizzare behavior on my Chrome. The following code causes the page to be refreshed on Chrome when I click on the add button which is not what I want it to do:

function addSpamAddr() 
{
    var email = prompt("Add Spam Address","");
    if (email == null || email == "")
        return false;

    var regex = /^[a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}$/;
    if (regex.test(email) == false) {
        alert("You must enter a valid E-Mail address");
        return false;
    }


    var listBox = document.getElementById('spamList');
    for (var x = 0; x < listBox.options.length; x++) {
        if (listBox.options[x].value == email || listBox.options[x].text == email) {
            alert("Already blocked address");
            return false;
        }
    }

    var selectBoxOption = document.createElement("option");
    selectBoxOption.value = email;
    selectBoxOption.text = email;
    listBox.add(selectBoxOption);

    return false;
}


...
<button style="margin-right: 20px;width:60px" onclick="addSpamAddr()">Add</button>

The code works perfectly fine on Internet Explorer. I’ve created a minimal example to further investigate the issue:

function addSpamAddr()
{
   return false;
}
...
<button style="margin-right: 20px;width:60px" onclick="addSpamAddr()">Add</button>

Still causes refresh on Chrome.

How can I prevent the refresh?

Edit: After I added the return statement inside the onclick event, the page no longer refreshes on the minimal example I created.

<button style="margin-right: 20px;width:60px" onclick="return addSpamAddr()">Add</button>

However, the page would still refresh if I apply my original code. Particularly, this part causes it:

    var listBox = document.getElementById('spamList');
    var exists = false;
    for (var x = 0; x < listBox.options.length; x++) {
        if (listBox.options[x].value == email || listBox.options[x].text == email) {
            alert("Already blocked address");
            return false;
        }
    }

How do I fix this?

Answer 1

write like this

function addSpamAddr()
{
   return false;
}
...
<button style="margin-right: 20px;width:60px" onclick="return addSpamAddr()">Add</button>

you for got to write "return addSpamAddr()" in your html cod which is updated by me