JavaScript RangeError - Maximum call stack size exceeded when using jQuery.post

When using jQuery's .post() function to submit my form data, I'm getting an Uncaught RangeError: Maximum call stack size exceeded.

I know this generally means recursion but I can't see where the recursion is happening.

I've put the post request into a function ( submitRequest() ) so I can submit data from 2 different points in the code. It originally resided inside the submit event and at that point worked perfectly. The error came as soon as I moved it outside.

Any ideas?

JavaScript code (with commented logs so you can see the flow) :

$(document).ready(function() {
    var downloadLink = '',
        downloadName = '',
        details,
        detailsSaved = false;

    $('.js--download').click(function(event) {
        var self = $(this);
        event.preventDefault();
        downloadLink = self.data('filePath'); // Store clicked download link
        downloadName = self.closest('.brochure').find('.brochure__name').html().replace('<br>', ' ');
        if (!detailsSaved) {
            $('#brochure-section').addClass('hide');
            $('#capture-section').removeClass('hide');
            $('html, body').animate({
                scrollTop: $("#capture-section").offset().top
            }, 500);
        } else {
            submitRequest();
        }
        return false;
    });

    $(".submit-btn").click(function(event) {
        var antiSpam = $('input[name=url]').val();
        if (antiSpam != "") {
            outputResultText('Error - Please leave the spam prevention field blank', 'error');
            proceed = false;
            event.preventDefault();
            return false;
        }        

        var name = $('input[name=name]').val(),
            company = $('input[name=company]').val(),
            email = $('input[name=email]').val(),
            phone = $('input[name=phone]').val(),
            proceed = true;

        if(name==""){
            $('input[name=name]').addClass("error");
            proceed = false;
        }
        if(phone==""){
            $('input[name=phone]').addClass("error");
            proceed = false;
        }
        if(email==""){
            $('input[name=email]').addClass("error");
            proceed = false;
        }

        if(!proceed) {
            outputResultText('Please check all required fields', 'error');
            event.preventDefault();
            return false;
        }

        event.preventDefault();
        if(proceed) {
            console.log('About to request'); // Logged out
            submitRequest();
        }

        return false;
    });

    //reset previously set border colors and hide all message on .keyup()
    $("input, textarea").keyup(function() {
        $(this).removeClass("error");
        $(".form-result").fadeOut(100);
    });

    function submitRequest () {
        console.log('Start submitRequest'); // Logged out

        if (!detailsSaved) {
            console.log('Details are NOT saved');
            post_data = {
                'name': name,
                'company': company,
                'phone': phone,
                'email': email,
                'brochure': downloadName,
                'brochure_url': downloadLink
            };
            details = post_data;
        } else {
            console.log('Details are saved');
            post_data = details;
            post_data['brochure'] = downloadName;
            post_data['brochure_url'] = downloadLink;
        }
        console.log('Posting data'); // Logged out
        // CRASH: Uncaught RangeError: Maximum call stack size exceeded 

        $.post(bcf_local_args['post_url'], post_data, function(response){ 
            console.log('Response received');
            if(response.type != 'error') {
                if (detailsSaved) {
                    outputAlert("Thank you for your request to receive our <strong>'"+downloadName+"'</strong> brochure.<br>We'll send you a copy soon to <strong>'"+email+"'</strong>, so please check your inbox.<br>Want it sent to a different email? Simply refresh the page and try again.");
                } else {
                    //reset values in all input fields
                    $('#brochure-capture-form input').val('');
                    $('#brochure-capture-form textarea').val('');
                    $('#capture-section').addClass('hide');
                    $('#brochure-section').removeClass('hide');
                    outputAlert("Thank you for your request to receive our <strong>'"+downloadName+"'</strong> brochure.<br>We'll send you a copy soon to <strong>'"+email+"'</strong>, so please check your inbox.");
                }
                if (!detailsSaved) {
                    detailsSaved = true;
                }
                $('html, body').animate({
                    scrollTop: $(".brochure__alert").offset().top
                }, 500);
            } else {
                outputResultText(response.text, response.type); 
            }
        }, 'json');
    }

    function outputResultText (text, status) {
        var output = '';
        if(status == 'error') {
            output = '<div class="error">'+text+'</div>';
        } else {
             output = '<div class="success">'+text+'</div>';
        }
        $(".form-result").hide().html(output).fadeIn(250);
    }

    function outputAlert (text) {
        var output = '<div>'+text+'</div>';
        $('.brochure__alert').hide().removeClass('hide').html(output).slideDown(250);
        setTimeout( function() {
            $('.brochure__alert').slideUp(250);
        }, 6500);
    }

    // function accessStorage(action, dataKey, dataValue) {
    //     if(typeof(Storage) === "undefined") {
    //         // No support for localStorage/sessionStorage.
    //         return false;
    //     } 
    //     if (action == 'store') {
    //         localStorage.setItem(dataKey, dataValue);
    //     } else if (action == 'retrieve') {
    //         return localStorage.getItem(dataKey);
    //     }
    // }
});