Question

When I want to redirect, the variable where is always udefined. But, for example, I want put that variable in alert(); it shows correct number.

code

var where = msg.txt;
window.location = "/page.php?id=".where; //this redirects to /page.php?id=undefined
alert(where); //it show correct number

Answer 1

In JavaScript, . is used for property access, not for string concatenation like in PHP.

Use + instead:

window.location = "/page.php?id=" + where;