pattern attribute in the lightning-input tag can be used o restrict users to avoid entering characters other than alphabets and number in Salesforce Lightning Web Component. Regular Expression should be used. In the following example, I have allowed alphabets and numbers alone.
Sample Code:
<template>
<div class=”slds-box slds-theme–default”>
<lightning-input
type=”text”
label=”String Only”
pattern=”[a-zA-z0-9]+”
message-when-pattern-mismatch=”Special Characters not allowed”>
</lightning-input>
</div>
</template>
<template>
<div class=”slds-box slds-theme–default”>
<lightning-input
type=”text”
label=”String Only”
pattern=”[a-zA-z0-9]+”
message-when-pattern-mismatch=”Special Characters not allowed”>
</lightning-input>
</div>
</template>
Output:
