How to use jQuery to onsubmit and check if the val

2020-02-09 07:40发布

Let's say I have a text field:

Username: <input type="text" id="username" class="required" />
<input type="submit" />

and I have some jQuery:

$(document).ready(function() {
    user = $("#username");

    user.submit(function() {

    })
})

I want to check if the length of the value entered in username is between 2 - 5 characters after I submit. If it's not then something happens.

I'm not too sure what I should be inside the user.submit(function(){}).

4条回答
We Are One
2楼-- · 2020-02-09 08:02

First you'll need an actual form:

<form id="myForm">
    Username: <input type="text" id="username" class="required" />
    <input type="submit" />
</form>

then:

$(document).ready(function(){
    $('#myForm').on('submit', function(e){
        e.preventDefault();
        var len = $('#username').val().length;
        if (len < 6 && len > 1) {
            this.submit();
        }
    });
});

Or in HTML5 you can use the pattern attribute (not supported in Safari and IE9-and below):

<form id="myForm">
    Username: <input type="text" id="username" pattern=".{2,5}" required />
    <input type="submit" />
</form>

FIDDLE

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smile是对你的礼貌
3楼-- · 2020-02-09 08:06

You can check the value of the input field with user.val() and the length of the string with user.val().length.

That way you can do something like this:

if(user.val().length < 2 || user.val().length > 5) {
    console.log('test')
} 
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地球回转人心会变
4楼-- · 2020-02-09 08:07

Bind submit to form instead of input type text and check its value in submit event. It would be better to assign some id to form and use form id selector to bind submit.

$('form').submit(function(){
      username = $('#username').val();
     if(username.length > 1 && username.length < 6)
     {
     }
});
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闹够了就滚
5楼-- · 2020-02-09 08:10

I made a Fiddle

You can use a statement as

$(document).ready(function(){  
    $("#form").submit(function(e) {
       length = $("#username").val().length;
       if((length > 2 && length < 5)) {
           $("#output").html("correct, logging in");
       } else {
           $("#output").html("incorrect, must have 3 or 4 chars");
       }
       return (length > 2 && length < 5);
    });
});

And HTML

<form id="form" method="POST" action="http://www.cnn.com">
username: <input type="text" id="username" class="required" />
<input type="submit" />

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