Question

我有一个输入字段，用户必须输入一个电话号码，而且必须是10个数字。我的脚本不起作用，我想知道如何指定＆＃39;确切的10＆＃39;部分。目前它还不到10个。

＆＃13;

 var contact_number = document.getElementById('number');
    input = contact_number.value
    if (input.length = 10){
        alert("The field needs to contain 10 numbers!")
        return false
    }else {
        return true
    }
    
    if (contact_number == ""){
        alert("You need to enter a Phone Number")
        return false;
    }

＆＃13;

<hr>

<!-- Clients details -->
	
    <p>Contact Person: <input id="contact" name="contact" type="text" placeholder="Type Full Name here"></p>
        
	
	<p>Contact Number: <input id="number" name="number" type="number" maxlength="10" placeholder="Type Number here"></p>
	
    
    <p>Email address: <input id="email" name="email" type="email" placeholder="Type Email here"></p>
    
<hr>

＆＃13;

Answer 1

您可以使用不等于运算符!=

 var contact_number = document.getElementById('number');
    input = contact_number.value
    if (input.length != 10){
        alert("The field needs to contain 10 numbers!")
        return false
    }else {
        return true
    }
    
    if (contact_number == ""){
        alert("You need to enter a Phone Number")
        return false;
    }

<hr>

<!-- Clients details -->
	
    <p>Contact Person: <input id="contact" name="contact" type="text" placeholder="Type Full Name here"></p>
        
	
	<p>Contact Number: <input id="number" name="number" type="number" maxlength="10" placeholder="Type Number here"></p>
	
    
    <p>Email address: <input id="email" name="email" type="email" placeholder="Type Email here"></p>
    
<hr>

Answer 2

看起来你的第一个if语句已关闭。我想你想要说不等于。你目前所拥有的不是比较，而是总是进入if语句的主体。

if (input.length != 10){
    alert("The field needs to contain 10 numbers!")
    return false
}

使用基本的JavaScript

2 个答案: