我正在尝试获取它,以便如果我输入以空格结尾的名称,文本字段将变为红色。大多数代码都有效,但只有一种方法似乎无效。
问题一定是在索引的最后一部分?
var NamePass = true;
function ValidateName() {
var BlankPass = true;
var GreaterThan6Pass = true;
var FirstBlankPass = true;
var BlankMiddleName = true;
if (document.getElementById('Name').value == "") {
BlankPass = false;
}
var Size = document.getElementById('Name').value.length;
console.log("Size = " + Size);
if (Size < 7) {
GreaterThan6Pass = false;
}
if (document.getElementById('Name').value.substring(0, 1) == " ") {
FirstBlankPass = false;
}
var LastIndex = document.getElementById('Name').value.lastIndexOf();
if (document.getElementById('Name').value.substring((LastIndex - 1), 1) == " ") {
FirstBlankPass = false;
}
string = document.getElementById('Name').value;
chars = string.split(' ');
if (chars.length > 1) {} else
BlankMiddleName = false;
if (BlankPass == false || GreaterThan6Pass == false || FirstBlankPass == false || BlankMiddleName == false) {
console.log("BlankPass = " + BlankPass);
console.log("GreaterThan6Pass = " + GreaterThan6Pass);
console.log("FirstBlankPass = " + FirstBlankPass);
console.log("BlankMiddleName = " + BlankMiddleName);
NamePass = false;
document.getElementById('Name').style.background = "red";
} else {
document.getElementById('Name').style.background = "white";
}
}
最佳答案
lastIndexOf
获取字符的最后一个索引,而不是字符串中的最后一个索引。我认为您打算改用 length
:
var lastIndex = document.getElementById('Name').value.<b>length</b>;
但是,另一个问题是 substring
采用开始和结束索引,而不是开始索引和子字符串长度。您可以改用 substr
,但 charAt
更简单:
if (document.getElementById('Name').value.<b>charAt</b>(lastIndex - 1) == " ") {
FirstBlankPass = false;
}
现在,进行一些通用的代码改进。不要以 true
开始所有变量并将它们有条件地设置为 false
,只需将它们设置为条件:
var NamePass = true;
function ValidateName() {
var value = document.getElementById('Name').value;
var BlankPass = value == "";
var GreaterThan6Pass = value.length > 6;
var FirstBlankPass = value.charAt(0) == " ";
var LastBlankPass = value.charAt(value.length - 1) == " ";
var BlankMiddleName = value.split(" ").length <= 1;
if (BlankPass || GreaterThan6Pass || FirstBlankPass || LastBlankPass || BlankMiddleName) {
console.log("BlankPass = " + BlankPass);
console.log("GreaterThan6Pass = " + GreaterThan6Pass);
console.log("FirstBlankPass = " + FirstBlankPass);
console.log("BlankMiddleName = " + BlankMiddleName);
NamePass = false;
document.getElementById('Name').style.background = "red";
} else {
document.getElementById('Name').style.background = "white";
}
}
还有几点需要注意:
- 使用
camelCase
变量名而不是PascalCase
可能是个好主意,后者通常为构造函数保留 blah == false
实际上应该写成!blah
- 空的
if
后跟else
也可以替换为if (!someCondition)
- 该函数看起来应该返回
true
或false
,而不是设置全局变量NamePass
倒数第二,你可以用一个正则表达式来总结这一切,但如果你打算根据实际错误向用户提供更具体的错误消息,那么我不会这样做。
function validateName() {
return /^(?=.{6})(\S+(\s|$)){2,}$/.test(document.getElementById('name').value);
}
最后——请记住,并不是每个人都有中间名,甚至不是每个人都有一个超过 6 个字符的名字,正如@poke 指出的那样。
关于javascript - 确保输入的名称不以空格结尾,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/16328089/