输入字段为空时禁用提交按钮

Question

I want to disable submit button when 4 input fields are nulls

<input type="text" name="val1" id="val1">
<input type="text" name="val2" id="val2">
<input type="text" name="val3" id="val3">
<input type="text" name="val4" id="val4">

submit button

<input name="contact" type="submit" id="contact" value="Update" style="padding:5px" class="sendButton" disabled />

I am using

            <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.1/jquery.min.js"></script>
        <script type="text/javascript">
        $(document).ready(function(){
            $('.sendButton').attr('disabled',true);

            $('#val1').keyup(function(){
                if($(this).val().length !=0){
                    $('.sendButton').attr('disabled', false);
                }
                else
                {
                    $('.sendButton').attr('disabled', true);        
                }
            })
            $('#val2').keyup(function(){
                if($(this).val().length !=0){
                    $('.sendButton').attr('disabled', false);
                }
                else
                {
                    $('.sendButton').attr('disabled', true);        
                }
            })
            $('#val3').keyup(function(){
                if($(this).val().length !=0){
                    $('.sendButton').attr('disabled', false);
                }
                else
                {
                    $('.sendButton').attr('disabled', true);        
                }
            })
            $('#val4').keyup(function(){
                if($(this).val().length !=0){
                    $('.sendButton').attr('disabled', false);
                }
                else
                {
                    $('.sendButton').attr('disabled', true);        
                }
            })
        });
        </script>

I think I am using wrongly. I put all ids in one function.

 $('#val1','#val2','#val3','#val4').keyup(function(){

this code is not working . any suggestion. how to use & and condition(val1 &val2 & val3 &val4) in these function?.

Answer 1

The way I would try and solve this is like this:

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.1/jquery.min.js"></script>
<script type="text/javascript">

    $("#val1").keyup(function(event) {
        validateInputs();
    });

    $("#val2").keyup(function(event) {
        validateInputs();
    });

    $("#val3").keyup(function(event) {
        validateInputs();
    });

    $("#val4").keyup(function(event) {
        validateInputs();
    });

    function validateInputs(){
        var disableButton = false;

        var val1 = $("#val1").val();
        var val2 = $("#val2").val();
        var val3 = $("#val3").val();
        var val4 = $("#val4").val();

        if(val1.length == 0 || val2.length == 0 || val3.length == 0 || val4.length == 0)
            disableButton = true;

        $('.sendButton').attr('disabled', disableButton);
    }
</script>

This way you will have a single place for checking your logic and not having to maintain it at N number of places if you diced to add more inputs later. And also a bit better solution would be to give your inputs the same class so you could do something like

$(".myInputs").keyup(function(event){
    validateInputs();
});

Here is a jsFiddle example: https://jsfiddle.net/moj2dnup/

Answer 2

You could use the pattern attribute you would also need to use the required attribute otherwise an input field with an empty value will be excluded from constraint validation . This will prevent your form from being submitted, however, it won't disable your button.

Example:

<input pattern=".{5,}"   required title="5 character minimum">
<input pattern=".{5,10}" required title="between 5 and 10 characters">

Answer 3

 $(document).ready(function(){ $('.sendButton').attr('disabled',true); $('.txtValues').keyup(function(){ var checkNull=false; $('.txtValues').each(function(index,input){ if($(this).val().length !=0)checkNull=true; }); if(checkNull){ $('.sendButton').attr('disabled', false); }else{ $('.sendButton').attr('disabled', true); } }); }); 

 <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.1/jquery.min.js"></script> <input type="text" name="val1" id="val1" class="txtValues"> <input type="text" name="val2" id="val2" class="txtValues"> <input type="text" name="val3" id="val3" class="txtValues"> <input type="text" name="val4" id="val4" class="txtValues"> <input name="contact" type="submit" id="contact" value="Update" style="padding:5px" class="sendButton" disabled /> 

Use a common css class for all inputs. Loop through inputs using $.each and check all values are null.