How do I clear the previous text field value after submitting the form with out refreshing the entire page?

try this:

Using jQuery:

You can reset the entire form with:

$("#myform")[0].reset();

Or just the specific field with:

$('#form-id').children('input').val('')

Using JavaScript Without jQuery

<input type="button" value="Submit" id="btnsubmit" onclick="submitForm()">

function submitForm() {
   // Get the first form with the name
   // Hopefully there is only one, but there are more, select the correct index
   var frm = document.getElementsByName('contact-form')[0];
   frm.submit(); // Submit
   frm.reset();  // Reset
   return false; // Prevent page refresh
}

You can set the value of the element to blank

document.getElementById('elementId').value='';

Assign empty value:

document.getElementById('numquest').value=null;

or, if want to clear all form fields. Just call form reset method as:

document.forms['form_name'].reset()