将js变量发送到php页面 - 无法正常工作

This is what my javascript looks like:

print "<script>function newpage(){

xmlhttp=new XMLHttpRequest();

var PageToSendTo = 'select_db.php?';
var MyVariable = 'variableData';
var VariablePlaceholder = 'variableName=';
var UrlToSend = PageToSendTo + VariablePlaceholder + MyVariable + '&tweet_id='" .     $id_num;

print "xmlhttp.open('GET', UrlToSend);
xmlhttp.send();
}</script>";

(it is in a php file hence the print statement)

This is what my form submission looks like: (again in a php statement)

print "<form action=\"select_db.php\" onSubmit=\"return newpage()\">";

The function newpage is not working.. I expected the variables to be sent over in the URL but the resulting URL is just select_db.php?

help, please.

try this onSubmit=\"newpage(); return false; \"

You are missing the initial <script> tag...

print "<script>function newpage(){

xmlhttp=new XMLHttpRequest();

var PageToSendTo = 'select_db.php?';
var MyVariable = 'variableData';
var VariablePlaceholder = 'variableName=';
var UrlToSend = PageToSendTo + VariablePlaceholder + VariablePlaceholder + '$tweet_id='" .     $id_num;

print "xmlhttp.open('GET', UrlToSend);
xmlhttp.send();
}</script>";

does that solve your problem ?