javascript 如何仅限制特殊字符和 (/,*,+)
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how to restrict special characters and ( /,*,+) only
提问by Pavan Alapati
We have one text Field.We know how to restrict special characters.But We need Allow alphabet and Numbers and hyphen(-) only.No need Sepcial characters but except (-) . Give me any idea.
我们有一个文本字段。我们知道如何限制特殊字符。但我们只需要允许字母和数字和连字符 (-)。不需要特殊字符，但 (-) 除外。给我任何想法。
Mycode:
我的代码：
$('#pduration').keydown(function (e) {
if (e.shiftKey || e.ctrlKey || e.altKey) {
e.preventDefault();
} else {
var key = e.keyCode;
if (keyCodeEntered == 45) {
// Allow only 1 minus sign ('-')...
if ((elementRef.value) && (elementRef.value.indexOf('-') >= 0))
return false;
else
return true;
}
}
});
If we tried this code it's restrict spectal charecters but it's allow -,/,+ Please guide me only allow number and alphabet and hyphen only
如果我们尝试此代码，它会限制特殊字符，但允许 -,/,+ 请指导我只允许数字和字母和连字符
采纳答案by qtgye
replace this section:
替换此部分：
if (keyCodeEntered == 45) {
// Allow only 1 minus sign ('-')...
if ((elementRef.value) && (elementRef.value.indexOf('-') >= 0))
return false;
{
else
return true;
}
with this:
有了这个：
// keys a-z,0-9 numpad keys 0-9 minus sign backspace
if ( ( key >= 48 && key <= 90 ) || ( key >= 96 && key <= 105 ) || key == 109 || key==8)
{
//return true;
}
else
{
//return false
}
})
回答by xiix
It's quite easy to do with regex pattern matching.
使用正则表达式模式匹配非常容易。
For JavaScript I recommend https://regex101.com/, and for regex in general i recommend Rubular for testing and learning.
对于 JavaScript，我推荐https://regex101.com/，对于正则表达式，我推荐使用 Rubular 进行测试和学习。
A Regex pattern consists looks like this:
正则表达式模式如下所示：
/pattern/flags
**First, declare a regex pattern*
**首先，声明一个正则表达式模式*
/<regex here>/
In order to capture only certain types of characters, we'll use character classes.
为了仅捕获某些类型的字符，我们将使用字符类。
/[<char class here]/
Then use this class to match first lowercase letter, first uppercase letter, first number or first "-" character.
然后使用这个类来匹配第一个小写字母、第一个大写字母、第一个数字或第一个“-”字符。
/[a-zA-Z0-9-]/
This will only catch the first character
这只会捕获第一个字符
Since we want all matching characters, we add the flag gfor global,
which will return allthe characters that match. A final pattern for getting all legalflags loosk like this:
由于我们想要所有匹配的字符，我们g为global添加了标志，它将返回所有匹配的字符。获取所有合法标志的最终模式如下所示：
/[a-zA-Z0-9-]/g
That's it for the pattern.
这就是模式。
In order to check if something contains illegal characters, like you asked, you can do something like this (both examples work):
为了检查某些内容是否包含非法字符，如您所问，您可以执行以下操作（两个示例都有效）：
function verifyIllegalCharacters (inputString)
{
// Copy the results from replace to new string
// It now holds the original string, minus all legal characters.
// Since they were overwritten by "".
var newStr = inputString.replace(/[a-zA-Z0-9-]/g, "");
// If length is 0, all legal characters were removed,
// and no illegal characters remain.
return (newStr.length == 0);
}
function verifyIllegalCharacters (inputString)
{
// Same, but here we instead check for characters
// NOT matching the pattern. Above we capture all legal chars,
// here we capture all illegal chars by adding a ^ inside the class,
// And overwrite them with "".
var newStr = inputString.replace(/[^a-zA-Z0-9-]/g, "");
// If the lengths aren't equal, something was removed
// If something was removed, the string contained illegal chars.
// Returns true if no illegal chars, else false.
return (newStr.length == inputString.length);
}
