Regular Expression Checking For Proper Extension Names

Question

I am an issue with my javascript calling valid extensions invalid when they should pass. Ive used this regular expression in server side code and it worked fine for me. I verified that the value the reg expression is checking against is valid as well.

Am I declaring reg expression wrong maybe in the javascript?

 var ck_name = /^.+\.((gdf)|(GDF))$/;
 var chldValue = chld.value.substring(chld.value.length - 4, chld.value.length);
    alert(chldValue);

    if (!ck_name.test(chldValue)) {
        errors[errors.length] = "File is NOT a GDF file";
}

Answer 1

Firstly, ^.+ is unnecessary and timewasting.

Second, your string is only four character long and what you are looking for... is a minimum of five characters long. Consequently they will never match.

Third, a regex is overkill.

Finally, your code should be:

if( chld.value.substr(chld.value.length-4).toLowerCase() != ".gdf")
    errors.push("File is NOT a GDF file");