在JavaScript中为乘法时间表添加起点和终点
[英]Add a starting and ending point for multiplication timetable in javascript
问题描述
For example - display the 4 times table starting at 5 (4*5) and ending at 9. 
例如-显示从5（4 * 5）开始到9结束的4次表。
- 4*5 = 20
- 4*6 = 24
- 4*7 = 28
- 4*8 = 32
- 4*9 = 36
I'm confused how to add start and end value. 我很困惑如何添加开始和结束值。
function printTable(){ var timesTable =Number(document.getElementById('txtNumber').value); for(var i=1; i<=10; i++){ var pTag= document.getElementById('pPrint'); pTag.innerHTML += (timesTable*i) + "<br/>" } }
<body style="text-align: center;"> <h1>JavaScript - Function to Display Table of an entered Number.</h1> <p><input type="text" id="txtNumber" placeholder="Enter number"/></p> <h1>enter the start value</h1> <p><input type="text" id="textNumber" placeholder="Enter number"/></p> <h1>enter the end value</h1> <p><input type="text" id="teextNumber" placeholder="Enter number"/></p> <p><input type="button" value="Print Table." onclick='printTable()'/> <!--print numbers--> <p id="pPrint"></p> </body>
How to add a starting and ending point for multiplication timetable in javascript? 如何在JavaScript中为乘法时间表添加起点和终点？
3 个解决方案
解决方案1
0 2018-11-15 02:58:50
If I understand your question correctly, perhaps you could do the following; 如果我正确理解了您的问题，也许您可以执行以下操作；
- Get the starting number via
Number(document.getElementById('textNumber').value)通过Number(document.getElementById('textNumber').value)获取起始编号 - Get the ending number via
Number(document.getElementById('teextNumber').value)通过Number(document.getElementById('teextNumber').value)获取结束号 - Use your for loop to start looping from the starting number to the ending number via
for(var i= start; i<= end; i++){使用for循环可通过for(var i= start; i<= end; i++){
You should also check that the starting number is less than the ending number to ensure the loop terminates: 您还应该检查起始编号是否小于结束编号，以确保循环终止：
function printTable(){ var start = Number(document.getElementById('textNumber').value); var end = Number(document.getElementById('teextNumber').value); var timesTable =Number(document.getElementById('txtNumber').value); // Query document for pTag once, rather than per loop iteration var pTag= document.getElementById('pPrint'); // Check that start is less than end, to ensure that the loop // terminates (ie doesn't loop infinitely) if(start < end) { for(var i= start; i<= end; i++){ // Present the multiplication in the required format pTag.innerHTML += ('- ' + i + ' * ' + timesTable + ' = ' + (timesTable*i) + '<br/>') } } }
<h5>JavaScript - Function to Display Table of an entered Number.</h5> <p><input type="text" id="txtNumber" placeholder="Enter number"/></p> <h5>enter the start value</h5> <p><input type="text" id="textNumber" placeholder="Enter number"/></p> <h5>enter the end value</h5> <p><input type="text" id="teextNumber" placeholder="Enter number"/></p> <p><input type="button" value="Print Table." onclick='printTable()'/> <p id="pPrint"></p>
解决方案2
0 已采纳 2018-11-15 02:59:09
If I understand your question correctly then I've add the multiplication function as following: 如果我正确理解了您的问题，那么我将添加乘法函数，如下所示：
function printTable(){ var ps =Number(document.getElementById('txtNumber').value); var start =Number(document.getElementById('textNumber').value); var end =Number(document.getElementById('teextNumber').value); for(var i=start; i<=end; i++){ var pTag= document.getElementById('pPrint'); pTag.innerHTML += "- " + (ps) + "*" + (i) + " = " + ps*i + "<br/>" } }
<body style="text-align: center;"> <h1>JavaScript - Function to Display Table of an entered Number.</h1> <p><input type="text" id="txtNumber" placeholder="Enter number"/></p> <h1>enter the start value</h1> <p><input type="text" id="textNumber" placeholder="Enter number"/></p> <h1>enter the end value</h1> <p><input type="text" id="teextNumber" placeholder="Enter number"/></p> <p><input type="button" value="Print Table." onclick='printTable()'/> <!--print numbers--> <p id="pPrint"></p> </body>
ps is the starting multiplication number, start is the starting number to times and end the ending number. ps是起始倍数，start是起始倍数，end是结束数。
Edit: add missing boxes 编辑：添加缺少的框
解决方案3
0 2018-11-15 03:06:40
Add starting point and ending point to for loop as below: 将起点和终点添加到for循环中，如下所示：
function printTable(){
var timesTable =Number(document.getElementById('txtNumber').value);
var start = document.getElementById("textNumber").value;
var end = document.getElementById("teextNumber").value;
for(var i=start; i<=end; i++){
var pTag= document.getElementById('pPrint');
pTag.innerHTML += (timesTable*i) + "<br/>"
}
} }
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