pass php variable to javascript [duplicate]

Answer 1

this.options[this.selectedIndex].value

Please pass the value of selected index like this

Answer 2

you have to put pid.value as the send function parameter like this

onclick="send(pid.value)"

Answer 3

Once the PHP renders into HTML it becomes less a question of passing PHP to Javascript and more a question or how to get the value from the HTML with Javascript. Would adding an onclick call to the function work for what you are trying to do?

<input type="submit" value="Submit" onclick="send(this.form.pid.value);return false;">