Jquery get form field value

Question

You have to use value attribute to get its value

<input type="text" name="FirstName" value="First Name" />

try -

var text = $('#DynamicValueAssignedHere').find('input[name="FirstName"]').val();

It can be much simpler than what you are doing.

HTML:

<input id="myField" type="text" name="email"/>

JavaScript:

// getting the value
var email = $("#myField").val();

// setting the value
$("#myField").val( "new value here" );

An alternative approach, without searching for the field html:

var $form = $('#' + DynamicValueAssignedHere).find('form');
var formData = $form.serializeArray();
var myFieldName = 'FirstName';
var myFieldFilter = function (field) {
  return field.name == myFieldName;
}
var value = formData.filter(myFieldFilter)[0].value;

$("form").submit(function(event) {
    
      var firstfield_value  = event.currentTarget[0].value;
     
      var secondfield_value = event.currentTarget[1].value; 
     
      alert(firstfield_value);
      alert(secondfield_value);
      event.preventDefault(); 
     });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form action="" method="post" >
<input type="text" name="field1" value="value1">
<input type="text" name="field2" value="value2">
</form>