当子字符串是连续的时，用javascript查找子字符串

Question

如果我试图检测＆＃34; http＆＃34;在一个字符串中。我正在尝试这个：

<?php foreach($rows as $row):;?>
<option value="<?php echo $row['Email'];?>"><?php echo $row['Email'];?></option>
<?php endfor;?>

如果缺少http，我想将http附加到字符串。

Answer 1

试，

     url_value = 'http://yadda/yaddayadda/a_site';
     substring = "http";
     substring_b = "https";
     if(url_value.indexOf(substring) >= 0 || url_value.indexOf(substring_b) >= 0)    { 
  **do something** 
     };

Answer 2

试试这个

＆＃13;

＆＃13;

function myFunction() {

     
      url_value = 'http://yadda/yaddayadda/a_site';
     substring = "http";
     if(url_value.search(substring) >= 0 ) { 
  alert("HELLO");
     };  
     
}

＆＃13;

<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

＆＃13;

＆＃13;

＆＃13;

Answer 3

这是我唯一可以上班的事情：

 if(url_value.substring(0,4) != substring && url_value.substring(0,5) != substring_b) { url_value = substring + url_value };

Answer 4

使用indexOf（）

url_value = http://yadda/yaddayadda/a_site
substring = "http";
substring_b = "https";
if(url_value.indexOf(substring) !== -1 || url_value.indexOf(substring_b) !== -1) { url_value = substring + url_value  };