Edit in JSFiddle

$(function () {
/**
 * Twitter Bootstrap Modal
 */
var Modal = (function ($) {
	var modal = $('#modal'), ele = {};
	// function checking
	if (!$.isFunction($.fn.modal)) {
		console.log('Twitter Bootstrap Modal is not loaded.');
		return false;
	}
	// initialize elements
	if (modal.length) {
		ele = {
			header: modal.find('#ModalLabel'),
			body: modal.find('div.modal-body:first'),
			submit: modal.find('[data-modal-action=submit]'),
			cancel: modal.find('[data-modal-action=cancel]')
		};
		ele.header.text('');
		ele.body.text('');
		ele.submit.show();
	}
	return {
		/**
		 * Show modal
		 * @param $option {object}:
		 *   message {string} Modal Context
		 *   header {string} Modal header
		 *   submit {object} (optional)
		 *      text {string} Button text
		 *      click {function} Button click function
		 *   cancel {object} (optional)
		 *      text {string} Button text
		 *      click {function} Button click function
		 */
		show: function (option) {
			// firing(reattach) events
			ele.submit.off('click').on('click', function () {
                // If you need submit the form
				//$(':button,:submit').prop('disabled', true);
			});
			//ele.cancel.off('click');

			// default setting
			var def = {
				message: 'Default Message',
				header: 'Default Header',
				submit: {},
				cancel: {
					text: 'Close'
				},
				keyboard: false,
				backgrop: 'static'
			};
			// combine arguments
			var args = $.extend(def, option);
console.log(args);
			// Twitter Bootstrap Modal option
			var opt = {
				keyboard: args.keyboard,
				backdrop: args.backdrop
			};

			// message must be string and filled
			if (args.message && 'string' === typeof args.message) {

				// message append
				ele.body.html(args.message);

				// header must be string
				if (args.header && 'string' === typeof args.header) {
					ele.header.text(args.header);
				}
				// hiring submit event
				if (args.submit.click && 'function' === typeof args.submit.click) {
					ele.submit.show();
					ele.submit.on('click', args.submit.click);
					// submit text
					if (args.submit.text && 'string' === typeof args.submit.text) {
						ele.submit.text(args.submit.text);
					}
				} else {
					ele.submit.hide();
				}
				// hiring cancel event
				if (args.cancel.click && 'function' === typeof args.cancel.click) {
					ele.cancel.on('click', args.cancel.click);
				}
				// cancel text
				if (args.cancel.text && 'string' === typeof args.cancel.text) {
					ele.cancel.text(args.cancel.text);
				}
				modal.modal(opt);
			}
			return false;
		},
		/**
		 * Close modal
		 */
		close: function () {
			modal.modal('hide');
		}
	};
}(jQuery));

    (function () {
        $('body').on('click', ':button', function () {
            var ele = {
                message: $('#message').val(),
                header: $('#header').val(),
                submit: {},
                cancel: {}
            };
            if ($('#submit-text').val()) {
                ele.submit.text = $('#submit-text').val();
                if ($('#submit-func').val()) {
                    ele.submit.click = function () {
                        eval($('#submit-func').val());
                    };
                }
            }
            if ($('#cancel-text').val()) {
                ele.cancel.text = $('#cancel-text').val();
                if ($('#cancel-func').val()) {
                    ele.cancel.click = function () {
                        eval($('#cancel-func').val());
                    };
                }
            }
            Modal.show(ele);
        });
    }());
});

<p>
    <input type="text" id="message" class="span2" placeholder="Message" value="Message" />
    <input type="text" id="header" class="span2" placeholder="Header" value="Header" /><br />
    <input type="text" id="submit-text" class="span2" placeholder="Submit button text" value="alert" /><br />
    <textarea id="submit-func" cols="50" rows="5" placeholder="Sumit function">alert('Hello, world!');</textarea><br />
    <input type="text" id="cancel-text" class="span2" placeholder="Cacen button text" /><br />
    <textarea id="cancel-func" cols="50" rows="5" placeholder="Cancel function"></textarea><br />
    <button class="btn">Call Modal</button>
</p>

<div id="modal" class="modal hide fade" tabindex="-1" role="dialog" data-backdrop="static" aria-labelledby="ModalLabel" aria-hidden="true">
    <div class="modal-header">
      <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>
      <h3 id="ModalLabel">Modal header</h3>
    </div>
    <div class="modal-body">
    </div>
    <div class="modal-footer">
      <button class="btn" data-dismiss="modal" aria-hidden="true" data-modal-action="cancel">No</button>
      <button class="btn btn-primary" data-modal-action="submit">Yes</button>
    </div>
  </div><!--//end modal.-->