function checkSpecialChar()

{

var allow=" abcdefghijklmnopqrstuvwxyz";

var my="sanThosh";

for(a=0;a<my.length;a++)

{

if(allow.indexOf(my.charAt(a))>0)

document.write(allow.indexOf(my.charAt(a)));

else

document.write('Special char');

document.write(my.charAt(a));

document.write('<BR>');

}