<input type="text" class="form-control nameValidation" placeholder="Name " id="txtName" name="txtName" />

<script>

    $(document).ready(function () {

//validation for Name field

$(".nameValidation").keypress(function(event){

var inputValue = event.which;

// allow letters and whitespaces only.

if(!(inputValue >= 65 && inputValue <= 122) && (inputValue != 32 && inputValue != 0)) { 

swal("Warning", "Please enter only alphabet characters", "warning");

}

});

//can paste only alphabet 

 

var alphaOnlyInput = document.getElementsByClassName('nameValidation');

var numofnameValidation = alphaOnlyInput.length;

alphaOnlyPattern = new RegExp('^[a-zA-Z ]+$');

let previousValue = '';

for (var i = 0; i < numofnameValidation; i++) {

var data=alphaOnlyInput[i];

data.addEventListener('input', (e) => {

let currentValue = data.value;

if (e.inputType.includes('delete') || alphaOnlyPattern.test(currentValue)) {

previousValue = currentValue;

}

data.value = previousValue;

});

}

//in name input alphabet validation

});

</script>