Pass Javascript variable to PHP via ajax

Question

I am trying to pass a variable from my javascript code over to the server side PHP code  I know this must be done via an ajax call which i believe i have done correctly  however accessing the variable i pass from my ajax into my php is when i run into trouble as i am new to php  Here is my code i have thus far     document  ready function                      clickable   click function                     var userID     this  attr  id                      alert   this  attr  id                       ajax                       type   POST                       url   logtime php                       data   userID     userID                      success  function data                                                alert  success                                                                             lt  php   logtime php  uid   isset   POST  userID       rest of code that uses  uid   gt    I m trying to pass my javascript variable  userID  to php   userID   however i ve gone wrong somewhere along the road  Thanks for the help

User · Answer

Since you re not using JSON as the data type no your AJAX call  I would assume that you can t access the value because the PHP you gave will only ever be true or false  isset is a function to check if something exists and has a value  not to get access to the value    Change your PHP to be    uid    isset   POST  userID         POST  userID     0    The above line will check to see if the post variable exists  If it does exist it will set  uid to equal the posted value  If it does not exist then it will set  uid equal to 0    Later in your code you can check the value of  uid and react accordingly  if  uid  0        echo  User ID not found       This will make your code more readable and also follow what I consider to be best practices for handling data in PHP

User · Answer

Pass the data like this to the ajax call  http   api jquery com jQuery ajax     data    userID   userID     And in your PHP do this   if isset   POST  userID            uid     POST  userID            Do whatever you want with the  uid     isset   function s purpose is to check wheter the given variable exists  not to get its value

User · Answer

To test if the POST variable has an element called  userID  you would be better off using array key exists    which actually tests for the existence of the array key not whether its value has been set    a subtle and probably only semantic difference  but it does improve readability   and right now your  uid is being set to a boolean value depending whether    POST  userID   is set or not     If I recall from memory you might want to try       uid    array key exists  userID     POST    POST  userID    guest     Then you can use an identifiable  guest  user and render your code that much more readable     Another point re isset   even though it is unlikely to apply in this scenario  it s worth remembering if you don t want to get caught out later     an array element can be legitimately set to NULL     i e  it can exist  but be as yet unpopulated  and this could be a valid  acceptable  and testable condition  but    a   array  one   gt 1   two   gt null   three   gt 3   isset a  one       true isset a  two       false  array key exists a  one       true array key exists a  two       true   Bw sure you know which function you want to use for which purpose

User · Answer

Alternatively  try removing  data  and making the URL  logtime php userID   userId  I like Brian s answer better  this answer is just because you re trying to use URL parameter syntax in  data  and I wanted to demonstrate where you can use that syntax correctly

User · Answer

document  ready function                     clickable   click function                     var userID     this  attr  id       you can add here your personal ID                   alert   this  attr  id                       ajax                       type   POST                       url   logtime php                       data                             action    my action                           userID   userID                                             success  function data                                                alert  success                             console log data                                                                             uid    isset   POST  userID         POST  userID      ID not found    echo  uid     uid add in your functions  note  if   is not supperted than add jQuery where   defined

[javascript] Pass Javascript variable to PHP via ajax

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