how do i check if document.getElementById('email2') exists before getting value

[jasonc]

is there a way to do this with javascript ?

var fID = document.getElementById('email2');

[codefossa]

if (window.document.getElementById("email2").value != undefined)
{
    // Do This
}

[web_craftsman]

var fID = document.getElementById('email2');
if (fID) {
  // do something with it's value
  alert(fID.value);
  // ...
}

[jasonc]

if (window.document.getElementById("email2").value != undefined)
{
    // Do This
}

 

hey thanks for the quick reply.

 

i tried that but got the following error message

 

Error: window.document.getElementById("email2") is null

 

 

sometimes the email2 field is not present on the form,  it would only be present if the user was not logged in already to confirm their email was correctly entered.  if they are logged in then there is only one field (email1) for the email not two (the other being email2)

[jasonc]

ah i think i got it working, but please confirm that this is correct before i use this.

 

if (document.getElementById("email2") != undefined)
{
    // Do This
}

[codefossa]

Yeah, sorry didn't realize I did that.  You should be good to go.

[jasonc]

great thank you for your help on this

[web_craftsman]

This

[js]

if (document.getElementById("email2") != undefined)

{

    // Do This

}

[/js]

is a more clumsy code for

[js]

if (document.getElementById("email2"))

{

    // Do This

}

[/js]

Because javascript will convert undefined to logical type false,  and not-null object(if element exists) - at true

[Adam]

You can also cut out the inevitable second call to getElementById in that situation with:

 

var el;
if (el = document.getElementById('...')) {
    // ...
}

[jasonc]

Thank you for all your replies, I have opted for

Kira

method.