我有一组文本字段，我正在其中进行验证 假设我有一个可以接受的名为“席位”的字段 值小于“99999”。这意味着我应该无法输入 “99999” 任何低于这个数字都可以。为此，我在下面写了 if 和 else if 。 请告诉我我是否做错了什么。从早上开始我就很困惑 是否应小于或大于
if ($("#seats").val() != '') {
setflag = false;
alert("Not a valid character")
}
else if($("#seats").val() < 99999) {
alert("Not a valid Number");
} else {
setflag = true;
}
从早上起我就很困惑它是否应该小于或大于`
这个可以接受值小于“99999”
我想你自己回答了......但是当它小于时它是有效。因此以下说法是错误的：
}elseif($("#seats").val() < 99999){
alert("Not a valid Number");
}else{
您是说如果它小于 99999，那么它是无效。你想做相反的事：
}elseif($("#seats").val() >= 99999){
alert("Not a valid Number");
}else{
此外，由于你有
$("#seats")var seats = $("#seats").val();
var error = null;
if (seats == "") {
error = "Number is required";
} else {
var seatsNum = parseInt(seats);
if (isNaN(seatsNum)) {
error = "Not a valid number";
} else if (seatsNum >= 99999) {
error = "Number must be less than 99999";
}
}
if (error != null) {
alert(error);
} else {
alert("Valid number");
}
// If you really need setflag:
var setflag = error != null;
这是一个工作示例：http://jsfiddle.net/LUY8q/
除了现有答案之外，还有一些内容。看看这个：
var seatsValid = true;
// cache the selector
var seatsVal = $("#seats").val();
if(seatsVal!=''){
seatsValid = false;
alert("Not a valid character")
// convert seatsVal to an integer for comparison
}else if(parseInt(seatsVal) < 99999){
seatsValid = false;
alert("Not a valid Number");
}
变量名 setFlag 非常通用，如果您仅将其与座位数结合使用，则应该重命名它（我将其称为席位验证）。我还将其初始化为 true，这消除了原始代码中最后的 else 的需要。接下来，我将选择器和对 .val() 的调用放入变量中。缓存选择器是一个很好的做法，这样 jquery 就不需要过多地遍历 DOM。最后，在比较两个值时，您应该尝试确保它们是相同的类型，在本例中，seatVal 是一个字符串，因此为了正确地将其与 99999 进行比较，您应该对其使用 parseInt() 。
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<form name="myform">
Enter your name
<input type="text" name="inputbox" id='textBox' value="" />
<input type="button" name="button" class="member" value="Click1" />
<input type="button" name="button" value="Click2" onClick="testResults()" />
</form>
<script>
function testResults(n) {
var answer = $("#textBox").val();
if (answer == 2) {
alert("Good !");
} else if (answer == 3) {
alert("very Good !");
} else if (answer == 4) {
alert("better !");
} else if (answer == 5) {
alert("best !");
} else {
alert('wrong');
}
}
$(document).on('click', '.member', function () {
var answer = $("#textBox").val();
if (answer == 2) {
alert("Good !");
} else if (answer == 3) {
alert("very Good !");
} else if (answer == 4) {
alert("better !");
} else if (answer == 5) {
alert("best !");
} else {
alert('wrong');
}
});
</script>
将小于运算符更改为大于或等于运算符：
}elseif($("#seats").val() >= 99999){
请参阅此答案。 val() 正在比较字符串，而不是数值。
If statement for images in jquery:
#html
<button id="chain">Chain</button>
<img src="bulb_on.jpg" alt="img" id="img"/>
#script
<script>
$(document).ready(function(){
$("#chain").click(function(){
if($("#img").attr('src')!='bulb_on.jpg'){
$("#img").attr('src', 'bulb_on.jpg');
}
else
{
$("#img").attr('src', 'bulb_onn.jpg');
}
});
});
</script>
如果你想用 css 属性制作一些 if else ，你可以这样做，这个程序用于使用 jquery 为某些文本制作突出显示按钮
HTML :
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
</head>
<style>
.myclass {
background-color: yellow;
font-weight: bold;
}
</style>
<body>
<h1>PTIK FKIP UNS</h1>
The
<span class="warna">Faculty of Teacher Training and Education</span>,<span class="warna">Sebelas Maret University</span>, Surakarta is an
<span class="warna">Educational Personnel Education Institution (LPTK)</span> which has 24 study programs in 6 majors. Each study program has its own characteristics in producing
<span class="warna">superior, strong and intelligent educational staff.</span>
<br> <br>
The <span class="warna">Informatics and Computer Technology Education (PTIK)</span> tudy program is planned to take shelter in the management of the
<span class="warna">Engineering and Vocational Education (PTK)</span> department. This placement revises our previous statement, where the PTIK study program is under the P.MIPA department. PTIK is a study program that will produce graduates who are
<span class="warna">prioritized to teach in vocational/vocational programs.</span>
So, it would be better if PTIK was under the PTK department which oversees vocational programs such as<span class="warna">Building Engineering Education,</span>and
<span class="warna">Mechanical Engineering Education </span>To meet the needs of lecturers in the field of information technology that cannot be met by the PTK department, PTIK will conduct
<span class="warna">resource sharing with the mathematics study program</span>
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
$("#Highlight").click(function(){
if($(".warna").hasClass('myclass')){
$(".warna").removeClass('myclass');
}
else
{
$(".warna").addClass('myclass');
}
});
});
</script>
<br><br>
<button id="Highlight">Highlight Paragraf</button>
</body>
</body>
</html>注意：如果你想在 jQuery 中使用“else if”，请确保你写：
else if ( yourTestHere )不是
elseif ( yourTestHere )空间很重要。