douliang2087 2017-05-30 10:16
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如何在php变量中保存javascript变量

I want to use javascript variable as php variable. I am echo php variable then its print. but when i am use for fetching data from database its show an error Notice: Undefined index: document.write(i)

here my code

javascript

var i=0;
function inc()
{
    i+=1;
}
<?php $foo="<script>document.write(i)</script>"; ?>

php

code work for

echo $foo

code not work for

$i=$foo;
$query="select * from TABLE where id = $i";
$result=mysqli_query($conn,$query);
while($row=mysqli_fetch_row($result))
    {
        echo $row[0];
    }

Then It show This Error Notice: Undefined index: document.write(i)

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2条回答 默认 最新

  • ds261634878 2017-05-30 10:28
    关注

    PHP is server-side code that is run to generate a page. Javascript is client-side code that is run after the page is sent to the visitor's browser. Javascript can't affect the server-side code because the server code is done running by the time the Javascript runs. If you want to have a user's selection change the behavior of the PHP code the next time the form is loaded, pass a variable through a $_POST variable when the form is submitted.

    If you want your PHP and Javascript code to be using the same value, have the PHP code write a Javascript variable initialization into the page's <head> section before any Javascript would run that would need to use it.

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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