An email address must not exceed 254 characters. This was accepted by the IETF following submitted erratum. A full diagnosis of any given address is available online. The original version of RFC 3696 described 320 as the maximum length, but John Klensin subsequently accepted an incorrect value, since a Path is defined as Path = … Read more
It drops the students table. The original code in the school’s program probably looks something like q = “INSERT INTO Students VALUES (‘” + FNMName.Text + “‘, ‘” + LName.Text + “‘)”; This is the naive way to add text input into a query, and is very bad, as you will see. After the values … Read more
I think you are attacking it from the wrong angle by trying to encode all posted data. Note that a “<” could also come from other outside sources, like a database field, a configuration, a file, a feed and so on. Furthermore, “<” is not inherently dangerous. It’s only dangerous in a specific context: when … Read more
2nd October 2020: note that many bare-bones approaches are fraught with subtle bugs (eg. whitespace, implicit partial parsing, radix, coercion of arrays etc.) that many of the answers here fail to take into account. The following implementation might work for you, but note that it does not cater for number separators other than the decimal … Read more
@Joel’s answer is pretty close, but it will fail in the following cases: // Whitespace strings: IsNumeric(‘ ‘) == true; IsNumeric(‘\t\t’) == true; IsNumeric(‘\n\r’) == true; // Number literals: IsNumeric(-1) == false; IsNumeric(0) == false; IsNumeric(1.1) == false; IsNumeric(8e5) == false; Some time ago I had to implement an IsNumeric function, to find out if … Read more