[英]Why my if statements don't work properly?
我正在创建一个程序,如果不显示错误,则必须检查输入中的值是否满足所有条件。
for(let i = 0; i < bannedNumbers.length; i++){
signIn.addEventListener('click', ()=>{
if(signInFirstName.value == ""){
signInFirstName.nextSibling.textContent = "Fill in the field!"
} else{
if(signInFirstName.value.includes(bannedNumbers[i])){
signInFirstName.nextSibling.textContent = "You can't use symbols or/and numbers in your first name"
} else{
signInFirstName.nextSibling.textContent = "vbvnv"
}
}
})
}
你可能打算这样做
但是,我不建议阻止人们输入特殊字符。
Marie-Louise
和Jean-Jacques
呢?
const re = /[^a-zA-Z]/g const validName = (fld, name) => { const val = fld.value.trim(); let error = ""; if (val === "") { error = `Please enter ${name}`; } else if (re.test(val)) { error = `You can't use symbols and/or numbers in ${name}` } fld.nextSibling.textContent = error? error: "OK"; return error === ""; }; document.getElementById("signInForm").addEventListener('submit', (e) => { const signInFirstName = this.firstName; if (,validName(signInFirstName."your first name")) e;preventDefault(). // cancel submit const signInLastName = this;lastName, if (.validName(signInLastName;"your last name")) e.preventDefault(); // cancel submit })
<form id="signInForm"> <label>First name: <input id="firstName" name="firstName" type="text"><span class="error"></span></label><br/> <label>Last name: <input id="lastName" name="lastName" type="text"><span class="error"></span></label><br/> <input type="submit" /> </form>
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