How does PHP HTML JavaScript MySQL code share methods that pass values to each other

1.PHP

a PHP - > HTML & JavaScript

Well, it's super easy. I'll also write = = ~

html code

< input type="" readonly="readonly" style='background-color:#DCDCDC' value= < ?php echo $perinfo[ID];? > / >
JavaScript code

 
<script type="text/javascript"> 
var ability=<?php echo JSON($array);?>; 
</script> 

b. PHP < - > MySQL

php code

 
<?php 
$dbcnx = @mysql_connect ( "localhost", "root", "1234" ); 
if (! $dbcnx) { 
echo ("Unable to connect to the " . "database server at this time."); 
exit (); 
} 

if (! @mysql_select_db ( "pms" )) { 
echo ("Unable to locate the joke " . "database at this time."); 
exit (); 
} 
mysql_query ( "SET NAMES 'GB2312'" ); 


$q=mysql_query("select * from ability where ALV = 1"); 
while($row=mysql_fetch_array($q)){ 
$array1[] = $row[AName]; 
} 
?> 

2.HTML

a HTML - > PHP (POST mode)

html code

 
<form id="form" name="form" method="POST" action="do.php"> 
<input type="hidden" id="count" name="count" value="1"/> 
<input type="submit" name="Submit" value="Search"/> 
</form> 

do.php file code

 
<?php 
echo $_POST['count']; 
?> 

b HTML - > JavaScript


JavaScript code (available, modifiable)

 
<script type="text/javascript"> 
var te = document.getElementById("count"); 
te.value = 1; 
</script> 

3.JavaScript

a JavaScript - > HTML (general method, not verified)

JavaScript code

 
<script type="text/javascript"> 
function f(){ 
var id = "2"; 
var a = document.getElementById("a"); 
a.href.replace("(n)", id); 
} 
</script> 

html code

 
<a id="a" href="ExportArticle.action?articles=(n)"/> 

b JavaScript - > PHP

Transfer via html

1. Give html the JavaScript code first

 
<script type="text/javascript"> 
var i = 1; 
var te = document.getElementById("count"); 
te.value = i; 
</script> 

2.html code to php

 
<form id="form" name="form" method="POST" action="do.php"> 
<input type="hidden" id="count" name="count" value="1"/> 
<input type="submit" name="Submit" value="Search"/> 
</form> 

3. do. php receives

 
<?php 
echo $_POST['count']; 
?>