I was attempting to complete a very simply javascript regular expression which removes a few characters from a string:

my_field_124  => my_field

So i created the following javascript:

fieldName.replace (/\_\d+/, '');
alert(fieldName);

What I thought would display is the string “my_field”. Instead I kept getting “my_field_1″ returned. The reason for this is that the replace() function returns the resulting value, and doesn’t change the value of the original string! Change the script to:

alert(fieldName.replace(/\_\d+, '');

And it works!