For循环似乎在某些范围内不起作用？
[英]For loop doesn't appear to work in certain ranges?
问题描述
I have this issue where running a for loop between some ranges of numbers does not work?
我有这个问题，在某些数字范围之间运行 for 循环不起作用？ The loop literally just does not execute, and I really can't explain why this occurs for some number ranges, but not others.循环实际上只是不执行，我真的无法解释为什么会在某些数字范围内发生这种情况，而在其他数字范围内则不然。 It seems that this only occurs in ranges where the upper value is < 100, and the lower is >=0.似乎这只发生在上限值< 100，下限值> = 0的范围内。 For example 20-100 does not work, yet 40-90 does.例如 20-100 不起作用，但 40-90 起作用。 I've removed a lot of the code (mainly value validation things) that doesn't need to be included, as my only real issue is as to why this loop doesn't work.我删除了很多不需要包含的代码（主要是值验证的东西），因为我唯一真正的问题是为什么这个循环不起作用。
I really don't even know what to try, I can't understand why calling createTable(20,100) doesn't execute the loop, whilst createTable(40,90) does...我真的不知道该尝试什么，我不明白为什么调用 createTable(20,100) 不会执行循环，而 createTable(40,90) 会...
I should also mention that this only occurs when clicking the "convert" button.我还应该提到，这只发生在单击“转换”按钮时。
To try this yourself, enter 20 as the lower value, 100 as the upper value, select "Celsius → Fahrenheit" and click convert.要自己尝试，请输入 20 作为下限值，输入 100 作为上限值，select "Celsius → Fahrenheit" 并单击转换。
var lowerValue = document.getElementById("lower"); var upperValue = document.getElementById("upper"); var celsiusCheckBox = document.getElementById("celsius"); var fahrenheitCheckBox = document.getElementById("fahrenheit"); var submitButton = document.getElementById("submit"); function onButtonClicked() { createTable(lowerValue.value, upperValue.value) } function createTable(lower, upper) { for(let i = lower; i <= upper; i++ ) { console.log(i); } } function checkCheckBox(element) { if (element.id == "celsius" && fahrenheitCheckBox.checked) { fahrenheitCheckBox.checked = false; } else if (element.id == "fahrenheit" && celsiusCheckBox.checked) { celsiusCheckBox.checked = false; } }
<;DOCTYPE html> <html lang="en"> <label>Lower value</label> <input type="text" id="lower"> <label>Upper value*</label> <input type="text" id="upper"> <label>Celsius → Fahrenheit</label> <input type="checkbox" id="celsius" onclick="checkCheckBox(this)"> <label>Fahrenheit → Celsius</label> <input type="checkbox" id="fahrenheit" onclick="checkCheckBox(this)"> <button type="button" id="submit" onclick="onButtonClicked()">Convert</button> <body> </body> </html>
Any help would be greatly appreciated.任何帮助将不胜感激。
2 个解决方案
解决方案1
2 已采纳 2021-02-16 14:57:39
This happens because you are passing strings to the function and "100" is < than "20" since it starts with 1 .发生这种情况是因为您将字符串传递给 function 并且"100" < "20" ，因为它以1开头。
Use利用
function onButtonClicked() {
const lower = parseInt(lowerValue.value, 10);
const uppdate = parseInt(upperValue.value, 10);
createTable(lowerValue.value, upperValue.value)
}
Updated snippet更新的片段
var lowerValue = document.getElementById("lower"); var upperValue = document.getElementById("upper"); var celsiusCheckBox = document.getElementById("celsius"); var fahrenheitCheckBox = document.getElementById("fahrenheit"); var submitButton = document.getElementById("submit"); function onButtonClicked() { const lower = parseInt(lowerValue.value, 10); const upper = parseInt(upperValue.value, 10); createTable(lower, upper) } function createTable(lower, upper) { for (let i = lower; i <= upper; i++) { console.log(i); } } function checkCheckBox(element) { if (element.id == "celsius" && fahrenheitCheckBox.checked) { fahrenheitCheckBox.checked = false; } else if (element.id == "fahrenheit" && celsiusCheckBox.checked) { celsiusCheckBox.checked = false; } }
<label>Lower value</label> <input type="text" id="lower"> <label>Upper value*</label> <input type="text" id="upper"> <label>Celsius → Fahrenheit</label> <input type="checkbox" id="celsius" onclick="checkCheckBox(this)"> <label>Fahrenheit → Celsius</label> <input type="checkbox" id="fahrenheit" onclick="checkCheckBox(this)"> <button type="button" id="submit" onclick="onButtonClicked()">Convert</button>
解决方案2
1 2021-02-16 15:07:41
The values are received as strings in createTable function, Convert them to integers and try, it will work.这些值在createTable function 中作为字符串接收，将它们转换为整数并尝试，它将起作用。
var lowerValue = document.getElementById("lower"); var upperValue = document.getElementById("upper"); var celsiusCheckBox = document.getElementById("celsius"); var fahrenheitCheckBox = document.getElementById("fahrenheit"); var submitButton = document.getElementById("submit"); function onButtonClicked() { createTable(lowerValue.value, upperValue.value) } function createTable(lower, upper) { lower = parseInt(lower); upper = parseInt(upper); for(let i = lower; i <= upper; i++ ) { console.log(i); } } function checkCheckBox(element) { if (element.id == "celsius" && fahrenheitCheckBox.checked) { fahrenheitCheckBox.checked = false; } else if (element.id == "fahrenheit" && celsiusCheckBox.checked) { celsiusCheckBox.checked = false; } }
<;DOCTYPE html> <html lang="en"> <label>Lower value</label> <input type="text" id="lower"> <label>Upper value*</label> <input type="text" id="upper"> <label>Celsius → Fahrenheit</label> <input type="checkbox" id="celsius" onclick="checkCheckBox(this)"> <label>Fahrenheit → Celsius</label> <input type="checkbox" id="fahrenheit" onclick="checkCheckBox(this)"> <button type="button" id="submit" onclick="onButtonClicked()">Convert</button> <body> </body> </html>
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