<script Language="Javascript">
var x = "1 2 3 4 a b 5 A B C ?=)(/&%%$$§!eogihwioprgh";
checkString(x);
function checkString(oldString){
var newString = "";
var charCode = "";
alert(oldString);
for(i=0;i<=oldString.length;i++){
charCode = oldString.charCodeAt(i);
if((charCode >= 48) && (charCode <= 57)){
newString += oldString.charAt(i);
}else if((charCode >= 65) && (charCode <= 90)){
newString += oldString.charAt(i);
}else if((charCode >= 97) && (charCode <= 122)){
newString += oldString.charAt(i);
}
}
alert(newString);
}
</script>