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angelsonearth

Regular Expression Test Method Not Working--Form Validation

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Hello there!  Please kindly note that I've been staring down this code for days now, and I can't seem to get why the regular expression test method doesn't work (and why Firebug says "it is not a function" when my code skips over everything that deals with the results of the test method). 

 

I am trying to create a utility function for form validation that passes in an id and a regular expression.  Here is my calling code:

 

regularExpressionMatchFunction("firstName", "/^[A-Za-z'\.]+\s*[A-Za-z'\.\s]*$/");
  

 

Here is the code with the erroneous component in bold:

 

function regularExpressionMatchFunction(id, regularExpressionMatch) {
    //declare variables used in field check.
    alert("At beginning of function, the regular expression is " + regularExpressionMatch);
    var fieldName;
    var fieldNameValue
    var regExFieldName
    var finalRegExpressBooleanFieldName
    var fieldNameValueTrimmed
    // Get field name and field value
    fieldName = document.getElementById(id);
    fieldNameValue = fieldName.value;
    // TRIM WHITE SPACE Function Called here-- prepare code for trimming off white space on fieldName value
    fieldNameValueTrimmed = trimWhiteSpace(fieldNameValue);
    alert("My fieldNameValueTrimmed is" + fieldNameValueTrimmed);
    // Now for the regular expression, which looks for letters, apostrophes, and periods, although I don't need to escape the period (plus white space
    // Have to change the fieldNameValue to trimmed version above
    
    // HERE IS ERROR HERE IS ERROR HERE IS ERROR
    // NOT RECOGNIZED AS A FUNCTION
    

finalRegExpressBooleanFieldName = regularExpressionMatch.test(fieldNameValueTrimmed);

 

    // EVERYTHING AFTER THE ABOVE CODE JUST GETS SKIPPED OVER, INCLUDING THE FOLLOWING ALERT MESSAGE
    alert("After doing regular expression MATCH, the value of finalRegExpressBooleanFieldName (the boolean) is " + finalRegExpressBooleanFieldName);
    // These alerts need to be replaced with calls to addErrorMessage and removeErrorMessage
    if (finalRegExpressBooleanFieldName == true) {
        //removeErrorMessage inserted here will take the element by id field but not an error message as arguments
        removeErrorMessage(id);
        alert("You are an awesome coder!");
    }
    else {
        // addErrorMessage will take the getElementById field "firstName" and also the error message as arguments
        addErrorMessage(id, "The name value must include alphabetical letters (and can include apostrophes, periods, and spaces)");
        alert("You code like toodles");
        // The return false code didn't work in the addErrorMessage function itself, so I'll try it here
        return false;
    }
}

 

If anyone can help me figure out why the code breaks at the test method in bold above, I would be most appreciative!

 

Thank you so very much!

 

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It's because the second argument you're passing to the function is a string literal, not a regular expression literal.

In PHP, you have to declare regexes as strings, but in JS, regexes have their own type (and should not be surrounded by quotes).

You would only ever use a string for a regex in JS if you're using the RegExp constructor, which you're not.

 

Short answer: If you want to do a regex literal, which I assume you do, take the quotes off the second parameter being passed to the function. That will fix that error.

 

As for the error message you're getting, you're getting it because there is no test method for strings in JS, just regexes.

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Dear Hartley Sans,

 

You are certainly all heart, Hartley Sans, and very, very much appreciated!  Between you and Larry Ullman, I think I stand a chance of becoming a serious Web coder one day!  Thanks so much, and bless your souls!

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