使用jQuery或JavaScript检查输入/类型文本是否为空/空 [英] Checking Input/Type Text is empty/null with jQuery or JavaScript

问题描述

我很困惑.我正在尝试检查我的JavaScript中输入的type:text是否为空或为null.我目前有这个:

I'm stumped. I'm trying to check to see if my input type:text is empty, or null, in my JavaScript. I currently have this:

        if ($("#startDate").val().trim().length() === 0)
    {
        alert("Please fill out the required fields.");
    }

我尝试过:.val() === ""，.val() == ""，.length() === 0，.length() == 0，.length() < 1，.val().length() === 0，val().trim().length() < 1，.trim().length() < 1，.text() === ""，.text() == ""，!$("#startDate").val()

I have tried: .val() === "", .val() == "", .length() === 0, .length() == 0, .length() < 1, .val().length() === 0, val().trim().length() < 1, .trim().length() < 1, .text() === "", .text() == "", !$("#startDate").val()

我的HTML是:

<fieldset>
<label for="startDate_[pk]" style="display:block; width:100%;text-align:left">Start Time</label>
<input type="text" name="startDate_[pk]" id="startDate_[pk]" style="width:75px;display:inline" placeholder="pick date" />
@@
<select name="startTime_[pk]" id="startTime_[pk]" style="display:inline;" disabled="disabled">
@{
var time = DateTime.Now.Date.AddHours(8);
for (int i = 480; i < 1260; i += 15)
{
<option value="@i">@DateTime.Now.Date.AddMinutes(i).ToShortTimeString()</option>
}
}
</select>
</fieldset>

我也尝试过这个:

        $('input[class^="dateValidate"]').each(function () {
        if($(this).val().trim().length === 0)
        {
            alert("Please fill out the required fields.");
        }

我的想法不多了.

****更新****

****Update****

验证适用于一个选定的对象.但是，当您选择多个对象时，验证仅适用于第一个对象.这是我的代码:

The validation works for one selected object. But when you select more than one, the validation only works for the first object. Here's my code:

    function validate()
{
    var startDate = $('[id^="startDate"]').filter(function(){
        return $(this).val().length!==0;
    });
    var showingType = $('[id^="tShowingType"]').filter(function () {
        return $(this).val() === "";
    });
    var startTime = $('[id^="startTime"]').filter(function () {
        return $(this).val() === "";
    });
    var endTime = $('[id^="endTime"]').filter(function () {
        return $(this).val() === "";
    });

    if (startDate.length == 0 || showingType.val() === "" || startTime.val() === "" || endTime.val() === "")
    {
        alert("Please fill out the required fields.");
    }
    else
    {
        UI.goToConfirmStep();
    }

我尝试过:

var startDate = $('[id^="startDate"]').filter(function(){
        return $(this).val().length!==0
var startDate = $('[id^="startDate"]').filter(function(){
        return $(this).val().length===0
startDate.length == 0
startDate.length < 0
startDate.length < 1

推荐答案

似乎选择器中的id映射错误startDate.在您的代码中，您具有诸如startDate_[pk]之类的ID.因此，您需要一个开头为的选择器，如下所示.

It seems that you have wrong id mapped- startDate in the selector. In your code you have IDs like startDate_[pk]. So you need a starts with selector like below.

 var emptyInputs= $('[id^="startDate"]').filter(function(){
     return $(this).val().length===0;
 });

if(emptyInputs.length>0){
   alert("Please fill out the required fields.");
}

小提琴演示

Fiddle Demo

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