我想+
和-
按钮和一个输入。输入需要开始为零。当我点击+
,需要多少由3增加,而当我点击-
,需要数减少1。
这里是我的尝试:
<div id="input_div">
<input type="text" size="25" value="1" id="count">
<input type="button" value="-" id="moins" onclick="minus()">
<input type="button" value="+" id="plus" onclick="plus()">
</div>
--------------------------------------------------------
var count = 1;
var countEl = document.getElementById("count");
function plus(){
count++;
countEl.value = count;
}
function minus(){
if (count > 1) {
count--;
countEl.value = count;
}
}
我的代码中的问题:1,从1开始(我想从0开始),当我按下2.加他加3(例如:1次点击加值为4),然后如果我点击再加上他只添加一(1点击加值为2)
您可以添加功能,这样的添加和删除基于该count
值类:
(点击“运行代码片断”来测试一下)
var count = 0;
var countEl = document.getElementById("count");
function plus() {
count += 3;
countEl.value = count;
calculateColor()
}
function minus() {
count--;
countEl.value = count;
calculateColor()
}
function calculateColor() {
removeClass(countEl, "red")
removeClass(countEl, "blue")
if (count < 0)
addClass(countEl, "red");
else if (count > 10 && count <= 15)
addClass(countEl, "red")
else if (count > 15)
addClass(countEl, "blue")
}
function addClass(element, className) {
element.classList.add(className);
}
function removeClass(element, className) {
element.classList.remove(className);
}
.red {
background-color: red
}
.blue {
background-color: blue
}
<div id="input_div">
<input type="text" size="25" value="0" id="count">
<input type="button" value="-" id="moins" onclick="minus()">
<input type="button" value="+" id="plus" onclick="plus()">
</div>
更改初始数量为0,改变count++
到count += 3
是这样的:
var count = 0;
var countEl = document.getElementById("count");
function plus(){
count += 3;
countEl.value = count;
}
function minus(){
if (count > 1) {
count--;
countEl.value = count;
}
}
改变你的输入元素0
太像这样的价值属性:
<input type="text" size="25" value="0" id="count">
你需要把价值0
在HTML
<input type="text" size="25" value="1" id="count">
^^^ change it to zero
你也需要改变count = 0
和'数+ = 3'
var count = 0;
var countEl = document.getElementById("count");
function plus(){
count+=3;
countEl.value = count;
}
function minus(){
if (count > 1) {
count--;
countEl.value = count;
}
}
<div id="input_div">
<input type="text" size="25" value="0" id="count">
<input type="button" value="-" id="moins" onclick="minus()">
<input type="button" value="+" id="plus" onclick="plus()">
</div>