Java Script Validation for Text Field

Java Script Validation for Text Field:

First we need to declare the Regular Expression for the Alphabetic validation like this,

var alphabetic = /^[a-zA-Z ]+$/;

Then we need to store our field value as a variable like this,

var fname=$('#edit-firstName').val(); 

Now we need to check whether the entered content is alphabetical or not,It will accept only alphabets..

if((fname == '') || (!alphabetic.test(fname))){
        errorCount = 1;
         error+= "You must supply a alphabetic value for the 'FullName' field of this form.";
    }