Exclude special characters in atextbox using RegExp

For example,

There is a textbox controld(id:txtName) which accepts all values except special characters like @, #

for this the RegExp should be like this:

function ExcludeSpecialCharacter()
{
var a = documnet.getElementById('txtName').value;
var aRegEx = /^[^\@\#]$/;

if(a != null)
{
if(!aRegEx.test(a))
{
alert("Name does not accept special characters like @ #.");
return false;
}
}
}