onKeyUp="this.value = this.value.toUpperCase()"

function capitalizeEachWord(str) {
    return str.replace(/wS*/g, function(txt) {
        return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase();
    });
}

function checkUpper()
{
var x = $x("P6_TEXT");
if (x.value.trim().substring(0,1) != x.value.trim().substring(0,1).toUpperCase()) {
    alert ('First letter Must be in upper case');
x.value = x.value.trim().substring(0,x.value.trim().length-1).toString();
}
}

onKeyUp="checkUpper();"