Javascript 如何限制输入文本框仅以Angular2形式输入数字?
我必须限制用户只在Angular2->form的字段中输入数字 我有解决方案,但退格在输入字段中不起作用 有人能找到合适的解决办法吗 form.htmlJavascript 如何限制输入文本框仅以Angular2形式输入数字?,javascript,angular,angular2-template,angular2-forms,angular2-services,Javascript,Angular,Angular2 Template,Angular2 Forms,Angular2 Services,我必须限制用户只在Angular2->form的字段中输入数字 我有解决方案,但退格在输入字段中不起作用 有人能找到合适的解决办法吗 form.html form.component.ts keyPress(event: any) { const pattern = /[0-9\+\-\ ]/; let inputChar = String.fromCharCode(event.charCode); // console.log(inputChar, e.charCod
form.component.ts
keyPress(event: any) {
const pattern = /[0-9\+\-\ ]/;
let inputChar = String.fromCharCode(event.charCode);
// console.log(inputChar, e.charCode);
if (!pattern.test(inputChar)) {
// invalid character, prevent input
event.preventDefault();
}
}
restrictNumeric = function (e) {
var input;
if (e.metaKey || e.ctrlKey) {
return true;
}
if (e.which === 32) {
return false;
}
if (e.which === 0) {
return true;
}
if (e.which < 33) {
return true;
}
input = String.fromCharCode(e.which);
return !!/[\d\s]/.test(input);
}
在kepress事件中,它限制用户只输入数字,但此代码的问题是退格,制表键不起作用。因此,此代码不符合我的预期…退格将不起作用,因为:
事件。charCode
不会映射到退格键的某个数字0-9
您需要将退格白名单(即keyCode=8)。类似这样的事情(在我脑子里):
我的答案是:-
form.html:
form.component.ts
keyPress(event: any) {
const pattern = /[0-9\+\-\ ]/;
let inputChar = String.fromCharCode(event.charCode);
// console.log(inputChar, e.charCode);
if (!pattern.test(inputChar)) {
// invalid character, prevent input
event.preventDefault();
}
}
restrictNumeric = function (e) {
var input;
if (e.metaKey || e.ctrlKey) {
return true;
}
if (e.which === 32) {
return false;
}
if (e.which === 0) {
return true;
}
if (e.which < 33) {
return true;
}
input = String.fromCharCode(e.which);
return !!/[\d\s]/.test(input);
}
restrictNumeric=函数(e){
var输入;
if(e.metaKey | | e.ctrlKey){
返回true;
}
如果(e.which==32){
返回false;
}
如果(e.which==0){
返回true;
}
如果(如<33){
返回true;
}
输入=String.fromCharCode(e.which);
返回!!/[\d\s]/.test(输入);
}
使用regex可以通过以下方式实现:
var numbersOnly=document.getElementById(“numbersOnly”);
numbersOnly.onkeyup=函数myFunction(){
numbersOnly.value=numbersOnly.value.replace(/[^0-9]/g');
};代码>
使用html5标签怎么样?
所有浏览器都支持它
你也可以用这种方法
keyPress(event: any) {
const pattern = /[0-9\+\-\ ]/;
let inputChar = String.fromCharCode(event.charCode);
if (!pattern.test(inputChar) && event.charCode != '0') {
event.preventDefault();
}
}
请不要再使用String.fromCharCode(event.keyCode),它被标记为已弃用,并且在Firefox 58中似乎无法正常工作。在Chrome和Firefox上测试的简单功能:
onKeypress(event: any) {
const keyChar = event.key;
let allowCharacter: boolean;
if (keyChar === "-" && event.target.selectionStart !== 0) {
allowCharacter = false;
}
else if (
keyChar === "Tab" ||
keyChar === "Enter" ||
keyChar === "Backspace" ||
keyChar === "ArrowLeft" ||
keyChar === "ArrowRight" ||
keyChar === "Delete") {
allowCharacter = true;
}
else {
allowCharacter = (keyChar >= '0' && keyChar <= '9');
}
if (!allowCharacter) {
event.preventDefault();
}
}
onKeypress(事件:任意){
const keyChar=event.key;
让allowCharacter:布尔值;
if(keyChar==“-”&&event.target.selectionStart!==0){
allowCharacter=false;
}
否则如果(
keyChar==“选项卡”||
keyChar==“输入”||
keyChar==“退格”||
keyChar==“箭头左”||
keyChar==“箭头右键”||
keyChar==“删除”){
allowCharacter=true;
}
否则{
allowCharacter=(keyChar>='0'&&keyChar我创建了一个只允许您键入数字的指令
import { Directive, ElementRef, HostListener, Input,OnInit,Renderer } from '@angular/core';
@Directive({
selector: 'input[app-numeric-field]'
})
export class NumericValidatorDirective implements OnInit {
@Input('app-numeric-field') maxLength: string;
constructor(private elementRef: ElementRef,private _renderer: Renderer) {}
ngOnInit(): void {
this._renderer.setElementAttribute(this.elementRef.nativeElement, 'maxlength', this.maxLength);
}
@HostListener('keydown', ['$event']) onKeyDown(event) {
let e = <KeyboardEvent> event;
if ([46, 8, 9, 27, 13, 110].indexOf(e.keyCode) !== -1 ||
// Allow: Ctrl+A
(e.keyCode === 65 && (e.ctrlKey || e.metaKey)) ||
// Allow: Ctrl+C
(e.keyCode === 67 && (e.ctrlKey || e.metaKey)) ||
// Allow: Ctrl+V
(e.keyCode === 86 && (e.ctrlKey || e.metaKey)) ||
// Allow: Ctrl+X
(e.keyCode === 88 && (e.ctrlKey || e.metaKey)) ||
// Allow: home, end, left, right
(e.keyCode >= 35 && e.keyCode <= 39)) {
// let it happen, don't do anything
return;
}
// Ensure that it is a number and stop the keypress
if ((e.shiftKey || (e.keyCode < 48 || e.keyCode > 57)) && (e.keyCode < 96 || e.keyCode > 105)) {
e.preventDefault();
}
}
}
import{Directive,ElementRef,HostListener,Input,OnInit,Renderer}来自“@angular/core”;
@指示({
选择器:“输入[应用程序数字字段]”
})
导出类NumericValidator指令实现OnInit{
@输入('app-numeric-field')最大长度:字符串;
构造函数(private elementRef:elementRef,private _renderer:renderer){}
ngOnInit():void{
this.u renderer.setElementAttribute(this.elementRef.nativeElement,'maxlength',this.maxlength);
}
@HostListener('keydown',['$event'])onKeyDown(event){
设e=事件;
如果([46,8,9,27,13,110].indexOf(e.keyCode)!=-1||
//允许:Ctrl+A
(e.keyCode===65&(e.ctrlKey | | e.metaKey))||
//允许:Ctrl+C
(e.keyCode===67&(e.ctrlKey | | e.metaKey))||
//允许:Ctrl+V
(e.keyCode===86&(e.ctrlKey | | e.metaKey))||
//允许:Ctrl+X
(e.keyCode===88&(e.ctrlKey | | e.metaKey))||
//允许:起始、结束、左、右
(e.keyCode>=35&&e.keyCode我做了一个指令来阻止特定的输入,类似于在这里和其他帖子中发布的其他输入。我基于我的,但做了一些更改,以避免使用不推荐的keyCode
属性,以及其他内容
我还取消了对允许的键盘命令的限制(包含Ctrl
、Command
、Shift
或Alt
)的任意组合键),因为这可能会导致意外的限制(例如无法执行撤消/重做命令)
以下是指令:
import { Directive, HostListener } from '@angular/core';
@Directive({
selector: '[inputDigitsOnly]',
})
export class InputDigitsOnlyDirective {
private static readonly allowedKeyCodes = [
"Backspace",
"Delete",
"Insert",
"ArrowUp",
"ArrowRight",
"ArrowDown",
"ArrowLeft",
"Tab",
"Home",
"End",
"Enter",
"Digit1",
"Digit2",
"Digit3",
"Digit4",
"Digit5",
"Digit6",
"Digit7",
"Digit8",
"Digit9",
"Digit0",
"Numpad0",
"Numpad1",
"Numpad2",
"Numpad3",
"Numpad4",
"Numpad5",
"Numpad6",
"Numpad7",
"Numpad8",
"Numpad9",
];
@HostListener('keydown', ['$event'])
onKeyDown(e: KeyboardEvent) {
// This condition checks whether a keyboard control key was pressed.
// I've left this 'open' on purpose, because I don't want to restrict which commands
// can be executed in the browser. For example, It wouldn't make sense for me to prevent
// a find command (Ctrl + F or Command + F) just for having the focus on the input with
// this directive.
const isCommandExecution = e.ctrlKey || e.metaKey || e.shiftKey || e.altKey;
const isKeyAllowed = InputDigitsOnlyDirective.allowedKeyCodes.indexOf(e.code) !== -1;
if (!isCommandExecution && !isKeyAllowed) {
e.preventDefault();
return; // let it happen, don't do anything
}
}
}
然后您只需要在输入中添加指令:
<input type="text" inputDigitsOnly>
你可以改变它来满足你的需要,你可以
希望有帮助。可能重复:可能重复我没有使用jQuery。typescript-angular2中有没有通过提供任何服务来解决问题的方法。这与Angular无关。无论如何,不要从用户手中接管键盘,阻止按键工作,让他认为键盘坏了。使用标准的HTML5技术,例如h作为type=“number”
,或模式来控制和验证输入。这也将正确处理代码无法处理的情况,例如自动填充或将文本拖放到输入框中。