Make sure to properly escape the colon in your selector.
Check out the Live Demo here
$( document ).ready(function() {
var color = $('#createOrderFormId\\:accountNo').css('border-color');
alert(color);
});
To include special characters like !"#\$%&'()*+,./:;<=>?@[]^`{|}~ in your selector, you need to escape them using two backslashes: \. For example, if you have an element with id="foo.bar", you would select it as $("#foo\.bar"). Make sure to refer to the W3C CSS specification for more details on valid selectors. Check this Reference.
Edit Instead of jQuery, you can also access the borderColor property using native JavaScript methods. You can retrieve the DOM object from a jQuery object by using .get() or indexing. Alternatively, you could use getElementById with the escape character, which worked for me in firefox.
View the updated Live Demo
$( document ).ready(function() {
alert( $('#createOrderFormId\\:accountNo')[0].style.borderColor);
alert(document.getElementById('createOrderFormId:accountNo').style.borderColor);
});