Javascript and PHP verify that the URL address entered by the user is correct

This article describes the example of Javascript and PHP validation user input URL address is correct method, share for your reference. The specific methods are as follows:

1. javascript detects URL address validity:

<script type="text/javascript">

function checkUrl() {

 var url = document.getElementById('url').value;

 if (url==''){

  alert('URL  Address cannot be empty ');

 return false;

 } else if (!isURL(url)) {

  alert('URL  The format of should be  https://www.ofstack.com');

 return false;

 } else {

  return true;

 }

 return false;

}

function isURL(str) 

{ 

 //varreg=/[0-9a-zA-z]+.(html|htm|shtml|jsp|asp|php|com|cn|net|com.cn|org)$/; 

 // Must contain .( Back face 1 A . At least in front 1 Characters ) And . At least in the back 1 Word characters, and finally 1 Characters must be word characters or /

 varreg=/w+.(w+|w+/)$/; 

 varisurl=reg.test(str);//test(str) The method is js The built-in object of the correct expression can be called directly  

 returnisurl; 

}

</script>
<form action="" method="post" onsubmit="checkUrl();">

 URL: 

 <input type="text" name="url" id="url" value="https://www.ofstack.com"  onfocus="this.value=''"/>

 <br /><br />

 <input type="submit" value=" Get the address " name="get"/>

 <input type="submit" value=" Download " name="download"/>

</form>

2. PHP Detects URL Address Validity

<?

function is_url($str){

return preg_match("/^http://[A-Za-z0-9]+.[A-Za-z0-9]+[/=?%-&_~`@[]':+!]*([^<>"])*$/", $str);

}

?>

If you want to try the normal method, we can use the file_get_contents () function to verify it.

I hope this article is helpful to everyone's PHP programming.