# toupper()

```
string toupper([string|node-set argument])
```

The `toupper` XPath function returns the uppercase equivalent of the Unicode representation of the argument. If no argument is given, the value of the current context node is used. As usual, parameters of type [`node-set`](http://www.w3.org/TR/xpath/#node-sets) are automatically cast to `string`. Parameters of other types, e.g. `number` or `boolean`, are not accepted.