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How can I check if an element exists in the visible DOM?
How do you test an element for existence without the use of the getElementById method?
25 Answers
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Load and execution sequence of a web page?
...execution sequence of an ordinary web page. But now I need to know detail. It's hard to find answers from Google or SO, so I created this question.
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How can I prevent SQL injection in PHP?
If user input is inserted without modification into an SQL query, then the application becomes vulnerable to SQL injection , like in the following example:
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What is the difference between JavaScript and ECMAScript?
...follow
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edited Jun 30 '13 at 3:21
Cole Johnson
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What is “vectorization”?
..., fortran ... some other ... but I've never found an explanation what does it mean, and what it does? So I'm asking here, what is vectorization, and what does it mean for example, that "a loop is vectorized" ?
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How can I make a div stick to the top of the screen once it's been scrolled to?
I would like to create a div, that is situated beneath a block of content but that once the page has been scrolled enough to contact its top boundary, becomes fixed in place and scrolls with the page.
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How can I use pointers in Java?
...Java doesn't have pointers, but I heard that Java programs can be created with pointers and that this can be done by the few who are experts in java. Is it true?
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Why are hexadecimal numbers prefixed with 0x?
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Short story: The 0 tells the parser it's dealing with a constant (and not an identifier/reserved word). Something is still needed to specify the number base: the x is an arbitrary choice.
Long story: In the 60's, the prevalent programming number systems were d...
How do I find the length of an array?
...f(a)/sizeof(*a)) << std::endl;
This doesn't work on pointers (i.e. it won't work for either of the following):
int *p = new int[7];
std::cout << "Length of array = " << (sizeof(p)/sizeof(*p)) << std::endl;
or:
void func(int *p)
{
std::cout << "Length of array ...
How to check if a process id (PID) exists
...ess, use
kill -0 $pid
But just as @unwind said, if you're going to kill it anyway, just
kill $pid
or you will have a race condition.
If you want to ignore the text output of kill and do something based on the exit code, you can
if ! kill $pid > /dev/null 2>&1; then
echo "Could ...