I have a TextBox and a Button:

![enter image description here](https://i.stack.imgur.com/yt7Sg.png)

If the value inside the Textbox is `1` (just emulating a condition)) I need to load jQuery on the fly and use a `document Ready` function : 

I tried this : 

```
function work() //when button click
{
        if (document.getElementById('tb').value == '1')
        {
                if (typeof jQuery == 'undefined')
                {
                        var script = document.createElement('script');
                        script.src = "http://code.jquery.com/jquery-git2.js";
                        document.getElementsByTagName('head')[0].appendChild(script);
                        $(document).ready(function ()
                        {
                                alert('');
                        });
                }
        }
}

```

But it says : 

`Uncaught ReferenceError: $ is not defined`

I assume it's because the line : `$(document).ready(function ()....`

But I don't understand why there is a problem , since i'm, loading jQuery BEFORE I use `$`...

**Question :** 

How can I fix my code to work as desired ?

[**JSBIN**](http://jsbin.com/ixUqOWU/2/edit)