在php中捕获js var

Question

Whats the best method of capturing a javascript variable sent using POST to a php file ?

My line of code that posts the variable is given below

 xmlHttp.open("GET", "testAJAX.php?$phpvariable="+$jsvariable, true);

Cheers

Answer 1

I'll bet the problem is you've confused yourself with the $ sign.

Change:

xmlHttp.open("GET", "testAJAX.php?$phpvariable="+$jsvariable, true);

To:

xmlHttp.open("GET", "testAJAX.php?phpvariable="+jsvariable, true);

Why?

Because calling $_GET['$phpvariable'] (single quotes) would give you the value of the parameter, whereas calling $_GET["$phpvariable"] (double quotes) would give you nothing! The $phpvariable inside double quotes would be assumed to be a PHP variable rather than a parameter name, and it would attempt to use the contents of the PHP variable (which probably doesn't exist) as the parameter name. (A parameter sent over HTTP is not a PHP variable.)

But if you don't include that $ in your request parameter name, then both single and double quotes will work: $_GET['phpvariable'] or $_GET["phpvariable"].

Also, Javascript variables don't begin with $ (not normally, although they can): I almost didn't catch that mistake.