Javascript function using regex

Question

I have created a function using reg-ex to validate a field in JavaScript. My function is

//FIRST NAME VALIDATION
var strFilter = /^[A-Za-z]*$/;
var fname = document.getElementById('fname');
fname = fname.value.replace(/^\s+|\s+$/g,'');

if ( ( !strFilter.test(fname.value) ) || fname == '') { 
    alert("Please enter a valid first name\r\n (only characters)");
    document.getElementById('fname').style.background = '#DFE32D';
    document.getElementById('fname').focus();
    document.getElementById('fname').value = '';
    return false;
}

Issue with the function is, it is taking stackoverflow234232 also as true. I want to constrain it for character only.

Answer 1

I think your problem is on this line -

if ((!strFilter.test(fname.value)) || fname == '') { 

it should be -

if ((!strFilter.test(fname) ) || fname == '') { 

fname is a string variable by the time you get to the if statement, so fname.value is returning undefined and the call to test is not working.

Answer 2

Try this instead

<!--   FIRST NAME VALIDATION   -->
var strFilter = /^[A-Za-z]*$/;
var fname = $('#fname');
fname.val(fname.val().replace(/^\s+|\s+$/g,''));


if ( ( !strFilter.test(fname.val()) ) || fname == '') {
    alert("Please enter a valid first name\r\n (only characters)");
    $('#fname').css('background-color','#DFE32D');
    $('#fname').focus();
    $('#fname').val('');
    return false;
}