javascript 如何使用 jQuery 只允许定义的字符作为输入？
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How to allow only defined characters as input using jQuery?
提问by net user
How do i allow special characters such as hyphen,comma,slash,space key,backspace key,delete key along with alphanumeric values and restrict the rest in jQuery?
我如何允许特殊字符，如连字符、逗号、斜线、空格键、退格键、删除键以及字母数字值并限制 jQuery 中的其余字符？
As this criteria(allowed characters/input values) varies from field to field, i would like to make it as a utility method which accepts input field id and allowed characters as parameters. for example: limitCharacters(textid, pattern)
由于此标准（允许的字符/输入值）因字段而异，我想将其作为一种实用方法，它接受输入字段 id 和允许的字符作为参数。例如：limitCharacters(textid, pattern)
回答by David Hellsing
?You can just check the keyCode on keydownand run preventDefault()if match:
?您可以只检查 keyCodekeydown并preventDefault()在匹配时运行：
$('input').keydown(function(e) {
if (e.which == 8) { // 8 is backspace
e.preventDefault();
}
});?
If you need to restrict to certain chars AND keyCodes + make it into a jQuery plugin, try something like:
如果您需要限制某些字符和 keyCodes + 使其成为 jQuery 插件，请尝试以下操作：
$.fn.restrict = function( chars ) {
return this.keydown(function(e) {
var found = false, i = -1;
while(chars[++i] && !found) {
found = chars[i] == String.fromCharCode(e.which).toLowerCase() ||
chars[i] == e.which;
}
found || e.preventDefault();
});
};
$('input').restrict(['a',8,'b']);?
回答by Undefined
I did something like this but in jQuery plugin format. This example will only allow numbers and full stops.
我做了这样的事情，但在 jQuery 插件格式。这个例子将只允许数字和句号。
You can call this by writing:
你可以这样写：
$("input").forceNumeric();
And the plugin:
和插件：
jQuery.fn.forceNumeric = function () {
return this.each(function () {
$(this).keydown(function (e) {
var key = e.which || e.keyCode;
if (!e.shiftKey && !e.altKey && !e.ctrlKey &&
// numbers
key >= 48 && key <= 57 ||
// Numeric keypad
key >= 96 && key <= 105 ||
// comma, period and minus, . on keypad
key == 190 || key == 188 || key == 109 || key == 110 ||
// Backspace and Tab and Enter
key == 8 || key == 9 || key == 13 ||
// Home and End
key == 35 || key == 36 ||
// left and right arrows
key == 37 || key == 39 ||
// Del and Ins
key == 46 || key == 45)
return true;
return false;
});
});
}
回答by elclanrs
I would suggest using Davidsolution for modifier keys like backspaceand deleteand this code below for characters:
我建议将David解决方案用于修饰键，例如退格键和删除键，以及下面的字符代码：
var chars = /[,\/\w]/i; // all valid characters
$('input').keyup(function(e) {
var value = this.value;
var char = value[value.length-1];
if (!chars.test(char)) {
$(this).val(value.substring(0, value.length-1));
}
});
Also, I've experienced some problems with keydownso I'd do it on keyup.
另外，我遇到了一些问题，keydown所以我会在keyup.
Demo:http://jsfiddle.net/elclanrs/QjVGV/(try typing a dot .or semicolon ;)
演示：http : //jsfiddle.net/elclanrs/QjVGV/（尝试输入点.或分号;）
