输入的最大值和最小值

Question

For this particular existing form there is an input to accept phone numbers. It already validates to only accept numbers and added a max character attribute for 10 characters.

However someone could add 1-9 digits. So I need to add javascript to check to make sure the character count for that field is 10. The input has an ID of phonenumber.

Can someone tell me how to modify the following code to make that work? Note: The "= 10 Characters" is just a placeholder, that part needs to be replaced with real code.

function checkEmail(theForm) {
    if (theForm.getElementById("phonenumber").value = 10 Characters )
    {
        alert('Your phone number is not 10 digits.');
        return false;
    } else {
        return true;
    }
}

Answer 1

我想你想要.length

if (theForm.getElementById("phonenumber").value.length == 10) { 

Answer 2

You may want to be gentle with your users, and allow common conventions in phone numbers, like spaces or dash-hyphens.

Just check for 10 digits. When you use the value, remove any non digits.

function checkphone(v){
    if(v.match(/\d/g).length==10) return true;
    throw 'Phone number must have 10 digits';
}

checkphone('207 555-5555');

Answer 3

if (theForm.getElementById("phonenumber").value.length != 10)

...因为长度不等于10时您希望发生某些情况。

Answer 4

Verify min and max length of phone number field using Javascript Validation

 function checkLimit() { var x, text; // Get the value of the input field with id="Phone" phone = document.getElementById("Phone").value; // If phone is Not a Number or less than 10 or greater than 10 if (isNaN(phone) || phone.length < 10 || phone.length > 10) { text = "Input not valid"; } else { text = "Input OK"; } document.getElementById("resp").innerHTML = text; } 

  <input onkeypress="checkLimit()" id="Phone" name="Phone" type="number" class="form-control" placeholder="Phone Number" required="required"/> <p id="resp"></p> 

Answer 5

try this:

function checkEmail(theForm) {
if (theForm.getElementById("phonenumber").value.length != 10 )
{
    alert('Your phone number is not 10 digits.');
    return false;
} else {
    return true;
}

}