Question

我正在展示alerts if 3 textboxes or any single text box is empty。例如：如果all are empty then alert will be" please fill up all" else if 1st and 2nd text boxes are empty then alert will be "please fill up 1st and 2nd text box" 同样if 1st and 3rd text boxes are empty then alert will be "please fill up 1st and 3rd text box" 同样if 2nd and 3rd text boxes are empty then alert will be "please fill up 2nd and 3rd text box" 同样if only 1st text box is empty then alert will be "please fill up 1st text box" 同样if only 2nd text box is empty then alert will be "please fill up 2nd text box" 同样if only 3rd text box is empty then alert will be "please fill up 3rd text box"

但问题是如果if-else statements，我必须在javascript中编写这么多number of text boxes are 10 or more。他们的任何解决方案是否最小化code和accordingly alert will come if any of the above condition satisfies？

我已经单独编写了if-else code，但它非常冗长：

 <form name="frm" action="confirmsubmit.jsp">
 <script type="text/javascript">
<!--
function confirmation() {
  var textboxname1=document.frm.textboxname1;
  var textboxname2=document.frm.textboxname2;
  var textboxname3=document.frm.textboxname3;

 //alert if all text boxes are empty

       if((textboxname1.value==null)||(textboxname1.value=="")&& (textboxname2.value=="")||(textboxname2.value==null)){
   alert("Please fill up first text box<br/>Please fill up second text box<br/>Please fill up 3rd text box");//alert for all
           textboxname1.focus();
           return false
       }

  //alert if 2nd text box is empty

         else if((textboxname2.value=="")||(textboxname2.value==null))
           {
 alert("Please Please fill up second text box");//alert for 2nd text box
           textboxname2.focus();
           return false 
           }              

   //alert if 3rd text box is empty   

         else if((textboxname3.value=="")||(textboxname3.value==null))
           {
 alert("Please Please fill up third text box");//alert for 3rd text box
           textboxname3.focus();
            return false 
           }  

          // similarly i have to show alert if 2nd and 3rd boxes are empty and so on, but is there any solution to minimize the code? 

            return true

   }
  //-->
  </script> 


<input type="text" name="textboxname1"/>
<input type="text" name="textboxname2"/>
<input type="text" name="textboxname3"/>
<input type="submit" onclick="return confirmation()"/> 
 </form>

Answer 1

伪代码：

emptyTextboxen = []

for each textboxen as textbox
    if textbox is empty
        emptyTextboxen.push(textbox)

if emptyTextboxen.length == textboxen.length
    message = 'Please fill up all textboxen'
else if emptyTextboxen.length > 0
    message = 'Please fill up textboxen '
    for each emptyTextboxen as emptyTextbox
        message += emptyTextbox + ', '
else
    message = 'Life is good'

Answer 2

检查每个空复选框使用这个简单的jquery选择器：

jQuery('input.test').not('[value]').each(function() {
    var blankInput = jQuery(this);
    //do what you want with your input
});

你的js会是这样的：

function confirmation(domForm) {
    var jForm = jQuery(domForm);
    var values = jForm.find('.check').serializeArray();

    var failedFields = [];
    for(var i = 0; i < values.length; i++) {
        var o = values[i];
        if(o.value == null || o.value.length == 0) {
            failedFields.push(o.name);
        }
    }

    if(failedFields.length > 0) {
        var message = ''; 
        if(failedFields.length == values.length) {
            message = 'fill all fields please';
        }
        else {
            message = 'please fill the fields:';
            for(var i = 0; i < failedFields.length; i++) {
                message += "\n";
                message += failedFields[i];
                }
        }

        alert(message);
        return false;
    }

    return true;
}

在你的提交上打电话确认！像这样：

<form name="frm" onsubmit="return confirmation(this)" action="confirmsubmit.jsp">
    <input type="text" name="textboxname1" class="check"/>
    <input type="text" name="textboxname2" class="check"/>
    <input type="text" name="textboxname3"/>
    <input type="submit"/> 
 </form>

Answer 3

也许这就是你要找的东西：

FIDDLE

$('form[name="frm"]').on('submit', function(e) {
    var empty = $('input[type="text"]', this).filter(function() {
        if ($(this).val()=="") return this;
    });
    if (empty.length > 0) {
        e.preventDefault();            
        if (empty.length == $(this).children('[type="text"]').length) {
            alert('please fill up all');
        }else{
            var str = 'please fill up ';
            $(empty).each(function(index, value) {
                var Sepa = index==empty.length-2 ? ' and ' : ', ',
                    Numb = parseInt(this.name[this.name.length-1]);
                Sepa = index==empty.length-1 ? '' : Sepa;                        
                Numb=Numb==1?'1st':Numb==2?'2nd':Numb==3?'3rd':Numb+'th';
                str=str+Numb+Sepa;
            });
            str=str+' text box';
            alert(str);                
        }   
    }else{
        alert('All are filled, form will be submitted');
    }
});

Answer 4

使用jQuery，你将能够做到这一点。要用最少的代码执行此操作，我建议采用以下方法。向所有文本框添加一个类，如果其中任何一个为空，则显示警告

<input type="text" name="textboxname1" class ="test"/>
<input type="text" name="textboxname2" class ="test"/>
<input type="text" name="textboxname3" class ="test"/>

并在脚本中

function confirmation() {
   var elements = $('.test');
   var index = 1;

   var message = "";
   elements.each(function(){
       if($(this).val() == ""){
        message += "textbox no" + index + "is empty ";          

       }

   index = index + 1;
   });
  if(message != ""){
   alert(message);
  }
}

如何在显示警报时最小化if-else语句

4 个答案: