How to conver alpabets into upper case using Java script?

The below function is used to convert the aplabets into upper case

function convertToUpper(){
var field1 = document.formName.elementName

field1.value = field1.value.toUpperCase();
}


Example :
If the formName is StudentForm and element name is student id like stud100

Then ,
function convertToUpper(){
var field1 = document.StudentForm.StudentId

field1.value = field1.value.toUpperCase();

}

gives the value as STUD100.