将php变量发送到javascript中

Question

<input type="button" name="Next" id="Next" value="Next" onclick="showNextQuest(<?php echo $_POST  ['$qtnid']; ?>)" />

$qtnid is the name of a radio button, i used the post method to know which one among the radio buttons is selected. The radio button has the same name with different values.It return an undefined error when itried to use alert function inside the showNextQuest function in the javascript. plz help me out.

Answer 1

<input type="button" name="Next" id="Next" value="Next" onclick="showNextQuest(<?php echo $_POST  ['$qtnid']; ?>)" />

should be

<input type="button" name="Next" id="Next" value="Next" onclick="showNextQuest('<?php echo $_POST  ['$qtnid']; ?>')" />

To make it a string, not a varname

Answer 2

如果值是字符串，那么如果要将值作为字符串传递，则还应该在PHP周围加上单引号：

showNextQuest('<?php echo $_POST['$qtnid']; ?>')