Javascript错误地验证日期

Question

我编写了一个函数来检查日期是否有效。

我只写了一小部分

这个函数不工作，我找不到错误，你能帮忙吗？

我可以看到，因为数字29不在数组中，所以它不起作用，但是我搞不懂如何使它工作。

​

function isValidDate() {
  var dateformat = /^(0?[1-9]|[12][0-9]|3[01])[-](0?[1-9]|1[012])[-]\d{4}$/;

  var readDate = document.getElementById("myDate").value;

  if (readDate.length <= 10) {
    <!--debug-->
    //console.log(readDate);

    /* split date into DD-MM-YYYY format */
    var splitDate = readDate.split('-');

    var day = splitDate[0];

    var month = splitDate[1];

    var year = splitDate[2];

    /* DEBUG - print split date into DD-MM-YYYY format */
    console.log('day ' + day);
    console.log('month ' + month);
    console.log('year ' + year);

    // Create list of days of a month [assume there is no leap year by default]  
    var ListofDays = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];

    //if month is between 1-12
    if (month == 1 || month < 13) {
      //check for invalid month
      if (month == 00) {
        console.log('0 - Invalid MONTH format!');
        return 0;
      }

      //check for invalid day
      if (day == 00) {
        console.log('0 - Invalid DAY format!');
        return 0;
      }

      //check DAY exists in the MONTH
      if (day > ListofDays[month - 1]) {
        console.log('1 - Invalid DATE format!');
        return 0;
      } else {
        console.log('1 - Valid DATE format!');
        return 1
      }
    } else {
      console.log("Invalid MONTH");
      return 0;
    }

    //check for leap year
    if (year % 4 === 0 && year % 100 !== 0) {
      console.log('The year ' + year + ' is a leap year.');
      return 1;
    } else if (year % 4 === 0 && year % 100 === 0 && year % 400 === 0) {
      console.log('The year ' + year + ' is a leap year.');
      return 1;
    } else {
      console.log('The year ' + year + ' is NOT a leap year');
      return 0;
    }
  } else {
    console.log("Invalid DATE length")
  }
}


/*    This is the only bit I did not write:
    
    	if (day > ListofDays[month-1])  
    	{  
        console.log('1 - Invalid DATE format!');  
        return 0;  
    	} 
    	else
        {
        console.log('1 - Valid DATE format!');  
        return 1
    }

*/

<p>Input a date and check it's in a)correct format and b)it is a valid date</p>

<input type="text" id="myDate" placeholder="DD-MM-YYYY"> <br><br>

<button type="button" onclick="isValidDate()"> Check Date </button>

​

Answer 1

1. 根据regex测试日期，您必须减少测试
2. 当您想要继续时不要返回

这里有一个解决方案，使代码尽可能接近您想要做的事情。我已经在注释中建议使用日期对象的更简单的解决方案，其他人已经对其进行了详细阐述。

​

function showError(str) {
  console.log(str)
  return false;
}

function isValidDate() {
  var dateformat = /^(0?[1-9]|[12][0-9]|3[01])[-](0?[1-9]|1[012])[-]\d{4}$/;

  var readDate = document.getElementById("myDate").value;

  if (readDate.length != 10) return showError("Invalid DATE length") // not correct length
  console.log(dateformat.test(readDate));

  if (!dateformat.test(readDate)) {
    return showError("Invalid DATE format") // not matching regex
  }

  /* split date into DD-MM-YYYY format */
  var splitDate = readDate.split('-');

  var day = splitDate[0];
  var month = splitDate[1];
  var year = splitDate[2];

  /* DEBUG - print split date into DD-MM-YYYY format */
  console.log('day ' + day);
  console.log('month ' + month);
  console.log('year ' + year);

  // Create list of days of a month [assume there is no leap year by default]  
  var ListofDays = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];

  //if month is not between 1-12
  if (month <= 0 || month > 12) {
    return showError('0 - Invalid MONTH format!');
  }

  var isLeap = false;
  //check for leap year
  if (year % 4 === 0 && year % 100 !== 0) {
    console.log('The year ' + year + ' is a leap year.');
    isLeap = true;
  } else if (year % 4 === 0 && year % 100 === 0 && year % 400 === 0) {
    console.log('The year ' + year + ' is a leap year.');
    isLeap = true;
  } else {
    console.log('The year ' + year + ' is NOT a leap year');
  }

  //check DAY exists in the MONTH
  var testDay = ListofDays[month - 1]; // array starts at 0
  // testDay += isLeap ? 1 : 0; // add one to testDay using ternary operator
  if (isLeap) testDay++; // less code, does the same as above
  if (day > testDay) {
    return showError('1 - Invalid DATE format!');
  }

  console.log('1 - Valid DATE format!');
  // You can return true here if you want


}

<p>Input a date and check it's in a)correct format and b)it is a valid date</p>

<input type="text" id="myDate" placeholder="DD-MM-YYYY"> <br><br>

<button type="button" onclick="isValidDate()"> Check Date </button>

​

Answer 2

把这些都扔掉。

<input type="date" />

工作完成了。

或者，由于您指定了格式，所以可以这样做：

var input = document.getElementById("myDate").value;
var parts = input.split("-");
var date = new Date(parts[2],parts[1]-1,parts[0]);
return date.getFullYear() == parts[2]
    && date.getMonth() == parts[1]-1
    && date.getDate() == parts[0];

这是因为JavaScript会“修正”日期，如果它超出了有效的界限(例如。1月32号被更正为2月1日)，所以只要看看它收到日期后是否有任何变化。

Answer 3

​

function validate(value) {
  var v = false;
  if (value) {
    var r = value.match(/([0-9]{1,2}).?([0-9]{1,2}).?([0-9]{4})/);
    
    if (r) {
      var day1 = parseInt(r[1]);
      var month1 = parseInt(r[2]);
      var year1 = parseInt(r[3]);

      var d = new Date(year1, month1 - 1, day1);

      var day2 = d.getDate();
      var month2 = d.getMonth() + 1;
      var year2 = d.getFullYear();

      v = day1    == day2   &&
          month1  == month2 &&
          year1   == year2;
    }
  }
  
  return v;
}

<input type="text" id="toCheck" />
<button onclick="console.log(validate(document.getElementById('toCheck').value))">Check</button>

​

您可以尝试使用任何分隔符，这只是一个例子(我使用了一个技巧来检查一个真正的日期)。您可以修改此函数以供个人使用。