我的最终目标是验证输入字段。输入可以是字母也可以是数字。
当前回答
当字符串以整数的表示形式开始时,parseInt提供整数:
(parseInt '1a') is 1
..所以也许:
isInteger = (s)->
s is (parseInt s).toString() and s isnt 'NaN'
(isInteger 'a') is false
(isInteger '1a') is false
(isInteger 'NaN') is false
(isInteger '-42') is true
原谅我的CoffeeScript。
其他回答
这就是你需要的。
var hasNumber = /\d/;
hasNumber.test("ABC33SDF"); //true
hasNumber.test("ABCSDF"); //false
Using Regular Expressions with JavaScript. A regular expression is a special text string for describing a search pattern, which is written in the form of /pattern/modifiers where "pattern" is the regular expression itself, and "modifiers" are a series of characters indicating various options. The character class is the most basic regex concept after a literal match. It makes one small sequence of characters match a larger set of characters. For example, [A-Z] could stand for the upper case alphabet, and \d could mean any digit.
从下面的例子
contains_alphaNumeric«它检查字符串是否包含字母或数字(或)字母和数字。连字符(-)将被忽略。 它检查字符串是否只包含任意序列顺序的字母和数字。
例子:
function matchExpression( str ) {
var rgularExp = {
contains_alphaNumeric : /^(?!-)(?!.*-)[A-Za-z0-9-]+(?<!-)$/,
containsNumber : /\d+/,
containsAlphabet : /[a-zA-Z]/,
onlyLetters : /^[A-Za-z]+$/,
onlyNumbers : /^[0-9]+$/,
onlyMixOfAlphaNumeric : /^([0-9]+[a-zA-Z]+|[a-zA-Z]+[0-9]+)[0-9a-zA-Z]*$/
}
var expMatch = {};
expMatch.containsNumber = rgularExp.containsNumber.test(str);
expMatch.containsAlphabet = rgularExp.containsAlphabet.test(str);
expMatch.alphaNumeric = rgularExp.contains_alphaNumeric.test(str);
expMatch.onlyNumbers = rgularExp.onlyNumbers.test(str);
expMatch.onlyLetters = rgularExp.onlyLetters.test(str);
expMatch.mixOfAlphaNumeric = rgularExp.onlyMixOfAlphaNumeric.test(str);
return expMatch;
}
// HTML Element attribute's[id, name] with dynamic values.
var id1 = "Yash", id2="777", id3= "Yash777", id4= "Yash777Image4"
id11= "image5.64", id22= "55-5.6", id33= "image_Yash", id44= "image-Yash"
id12= "_-.";
console.log( "Only Letters:\n ", matchExpression(id1) );
console.log( "Only Numbers:\n ", matchExpression(id2) );
console.log( "Only Mix of Letters and Numbers:\n ", matchExpression(id3) );
console.log( "Only Mix of Letters and Numbers:\n ", matchExpression(id4) );
console.log( "Mixed with Special symbols" );
console.log( "Letters and Numbers :\n ", matchExpression(id11) );
console.log( "Numbers [-]:\n ", matchExpression(id22) );
console.log( "Letters :\n ", matchExpression(id33) );
console.log( "Letters [-]:\n ", matchExpression(id44) );
console.log( "Only Special symbols :\n ", matchExpression(id12) );
把:
Only Letters:
{containsNumber: false, containsAlphabet: true, alphaNumeric: true, onlyNumbers: false, onlyLetters: true, mixOfAlphaNumeric: false}
Only Numbers:
{containsNumber: true, containsAlphabet: false, alphaNumeric: true, onlyNumbers: true, onlyLetters: false, mixOfAlphaNumeric: false}
Only Mix of Letters and Numbers:
{containsNumber: true, containsAlphabet: true, alphaNumeric: true, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: true}
Only Mix of Letters and Numbers:
{containsNumber: true, containsAlphabet: true, alphaNumeric: true, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: true}
Mixed with Special symbols
Letters and Numbers :
{containsNumber: true, containsAlphabet: true, alphaNumeric: false, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: false}
Numbers [-]:
{containsNumber: true, containsAlphabet: false, alphaNumeric: false, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: false}
Letters :
{containsNumber: false, containsAlphabet: true, alphaNumeric: false, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: false}
Letters [-]:
{containsNumber: false, containsAlphabet: true, alphaNumeric: true, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: false}
Only Special symbols :
{containsNumber: false, containsAlphabet: false, alphaNumeric: false, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: false}
java正则表达式模式匹配。
无论如何,它都不是刀枪不入的,但它对我来说是有效的,也许它会帮助到别人。
var value = $('input').val();
if(parseInt(value)) {
console.log(value+" is a number.");
}
else {
console.log(value+" is NaN.");
}
检查它的一种方法是遍历字符串并在命中数字时返回true(或false,这取决于您想要什么)。
function checkStringForNumbers(input){
let str = String(input);
for( let i = 0; i < str.length; i++){
console.log(str.charAt(i));
if(!isNaN(str.charAt(i))){ //if the string is a number, do the following
return true;
}
}
}
我们可以使用!/[^a-zA-Z]/.test(e)来检查它。 只需运行snippet并检查。
handleValueChange() { 如果(! / [^ a-zA-Z] / test (. getelementbyid(“textbox_id”)value)) { var x = document.getElementById('result'); x.innerHTML = '字符串不包含数字'; }其他{ var x = document.getElementById('result'); x.innerHTML = 'String does contains number'; } } 输入{ 填充:5 px; } <input type="text" id="textbox_id" placeholder="Enter string here…" oninput="handleValueChange()" > < p id = "结果" > < / p >