My code has been given below . Why i am getting undefined? Please help me out.

//HTML is here

 <input type="hidden" id="element_id">

//Jquery code is here

$('#student_update_form').on('submit', function(event) {

    event.preventDefault();

        var id = $(this).attr("element_id");
        alert(id);

});

My code has been given below . Why i am getting undefined? Please help me out.

//HTML is here

 <input type="hidden" id="element_id">

//Jquery code is here

$('#student_update_form').on('submit', function(event) {

    event.preventDefault();

        var id = $(this).attr("element_id");
        alert(id);

});

• javascript
• html
• jquery

Share Improve this question Follow asked Jun 19, 2020 at 3:53 MsM RobinMsM Robin 2911 silver badge66 bronze badges 3

• using $(this) here you are referring to form not your hidden input field . – Swati Commented Jun 19, 2020 at 3:56
• What are you trying to achieve, and how does your form looks like? – Thum Choon Tat Commented Jun 19, 2020 at 3:56
• What exactly you want to get? As per your code, you will get the value of "element_id" appended to the form. Describe what exactly you want to do. – Manikanta Chinta Commented Jun 19, 2020 at 3:57

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3 Answers 3

Sorted by: Reset to default 3

Short answer: just

$('#element_id').attr('id')

To selects a single element with the given id attribute:

$('#id')

it equivalent to document.getElementById() in Javascript: https://api.jquery./id-selector/

To get the value of an attribute for the first element in the set of matched elements or set one or more attributes for every matched element.

.attr()

https://api.jquery./attr/

You get undefined because

• $(this) does not refer to <input type="hidden" id="element_id">, it refer to the form has id='student_update_form'
• and this form does not has an attribute named: element_id, so js return undefined

You can try:

var id = $('#element_id').attr('id');
alert(id);

$('#student_update_form').on('submit', function(event) {

    event.preventDefault();

        var id = $("#element_id").val();
        alert(id);

});

There's no need to use attr, you can use id directly.