There is no a single hole on the character on punched tape, so a completely new tape which wasn't punched is totally filled with null characters. This way, the text could often be "inserted" at a specially kept for this space of null characters by punching the new characters into the tape, covering the nulls. Nowadays the null character is of primer importance in C and its derivatives and in many data formats as well. There it plays a role of the reserved character which function is to show the end of a string, which is frequently called a null-terminated string.
This way the string can be as long as it is needed with just the overhead of one byte. If a null character is represented, there is no guarantee that the resulting string will be properly interpreted. It happens because lots of programs will consider the null as the end of the string. Set a breakpoint in verify - does the function get called? Anyway, there doesn't seem to be anything wrong in the code you've shown us codepen. Add a comment. Active Oldest Votes.
Improve this answer. Mr Jerry Mr Jerry 1, 3 3 gold badges 14 14 silver badges 22 22 bronze badges. Community Bot 1 1 1 silver badge. But the OP only needs to check for "", the value of a form control will never be anything other than a string.
RobG RobG k 30 30 gold badges silver badges bronze badges. If you know you're in an ES5 environment. This worked for me Demo if! Rajender Joshi Rajender Joshi 4, 1 1 gold badge 21 21 silver badges 38 38 bronze badges. In any case, the following works Try to check for the length property if! Sushanth -- Sushanth -- The reason for this is simple: null doesn't exist for value types.
As we have seen previously, a reference is a pointer to a memory-address that stores a value e. If a reference points to null , then no value is associated with it. On the other hand, a value is, by definition, the value itself. There is no pointer involved. A value type is stored as the value itself. Therefore the concept of null doesn't exist for value types. The following picture demonstrates the difference. On the left side you can see again the memory in case of variable name being a reference pointing to "Bob".
The right side shows the memory in case of variable name being a value type. As we can see, in case of a value type, the value itself is directly stored at the address A0A1 which is associated with variable name. There would be much more to say about reference versus value types, but this is out of the scope of this article. Please note also that some programming languages support only reference types, others support only value types, and some e.
C and Java support both of them. The concept of null exists only for reference types. It doesn't exist for value types. Suppose we have a type person with a field emailAddress.
Suppose also that, for a given person which we will call Alice, emailAddress points to null. As we have seen already, what we can assert is that no value is associated with emailAddress. But why is there no value? What is the reason of emailAddress pointing to null? If we don't know the context and history, then we can only speculate. The reason for null could be:. In practice we often know the application and context.
We intuitively associate a precise meaning to null. In a simple and flawless world, null would simply mean that Alice actually doesn't have an email address. When we write code, the reason why a reference points to null is often irrelevant. We just check for null and take appropriate actions. For example, suppose that we have to write a loop that sends emails for a list of persons. The code in Java could look like this:.
We just acknowledge the fact that there is no email address, log a warning, and continue. If a reference points to null then it always means that there is no value associated with it. In most cases, null has a more specific meaning that depends on the context. In this case, returning null or an empty list is ambiguous. Does it mean that the patient doesn't have allergies, or does it mean that an allergy test has not yet been performed?
These are two semantically very different cases that must be handled differently. Or else the outcome might be life-threatening. Just suppose that the patient has allergies, but an allergy test has not yet been done and the software tells the doctor that 'there are no allergies'.
Hence we need additional information. We need to know why the function returns null. It would be tempting to say: Well, to differentiate, we return null if an allergy test has not yet been performed, and we return an empty list if there are no allergies. The different semantics for returning null versus returning an empty list would need to be well documented. And as we all know, comments can be wrong i. There is no protection for misuses in client code that calls the function.
For example, the following code is wrong, but it compiles without errors. Improve this answer. Community Bot 1 1 1 silver badge. I loved TamperData. Pacerier Nope. Closest I've been able to get is tripping the debugger on 'All xmlhttprequests' and tracing it back to the source JavaScript.
Nothing has matched up to it so far. Add a comment. Jonathan H. You can use an HTML entity. My guess is that your testers need to script the task. That is not a null character. It is the HTML entity representation of a null character. Pierre Ernst Pierre Ernst 3 3 silver badges 7 7 bronze badges. I want something QA testers can actually type in their browser. If you want the QA tester to have more freedom choosing which field should receive the NULL byte consider implementing an ASP page that would automatically parse the query string and build an auto-submitting form like the one provided — Pierre Ernst.
If paste is not an option, can a null byte be simply typed via some control sequence? Use AJAX to submit the form. Hopefully this helps in building the view you're looking for.
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