CODEWITHSUNDEEP
jquery
scriptkiddie
scriptkiddie

Reputation: 605

jquery : cannot read property of undefined

I want to read a value of a input in a form.

sometimes the the form contains the input

<form id="myform">
  <input type="text" name="username">
  <input type="hidden" name="userid" value="123">
</form>

sometimes the above input will not be in the form

<form id="myform">
  <input type="text" name="username">
</form>

My problem is

I am reading the userid value which throws the error if the input is not there.

var form = document.getElementById("myform");
userid = form.userid.value;

Because of this error most of the script functionality is not working.

if(pack_id !=undefined && pack_id ==''){
  pack_id=0;    
}

please help me rectify the error

Upvotes: 1

Views: 809

Answers (4)

Parthasarathy
Parthasarathy

Reputation: 318

var userIdCheck=$('#userId').val();
if(userIdCheck!=='undefined'){
alert("Ther is a input"+userIdCheck);
}
else{
alert("User Id does not contain the value");
}

Try this may helps you

Upvotes: 1

Haresh Vidja
Haresh Vidja

Reputation: 8496

you can check it by typeof method for userid property is exist or not in form JavaScript dom element object.

var form = document.getElementById("myform");
userid="";
if(typeof form.userid !=="undefined" )
{
    userid = form.userid.value;
}

Upvotes: 1

Keshav
Keshav

Reputation: 831

You can apply undefined check before getting value 

if(form.userid!=undefined){
userid = form.userid.value;
}

Upvotes: 1

guradio
guradio

Reputation: 15565

var ext = $('input[name=userid]').length;


if (ext) {
  alert('input is here')

} else {

  alert('not input is here')
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form id="myform">
  <input type="text" name="username">
</form>

Check the length like $('input[name=userid]').length of the input it present or not

Upvotes: 1

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