if input string is like
123karthik
alert ('correct format');
else if input string is like
开发者_运维百科karthik123
alert('Invalid format')
var regex = /[0-9]+[a-z]+/;
regex.test("karthik123") ? alert("yep") : alert("oops");
Try this... It works for me :) I don't know why people kept marking your question down. It was pretty simple to understand what you wanted.
<!DOCTYPE html>
<html>
<head>
<script language="JavaScript1.2">
function checkMe(){
var numChar=/^\d{3}\w+$/
if (document.myform.myinput.value.search(numChar))
alert("Please enter valid input inside form")
}
</script>
</head>
<body>
<form name="myform">
<input type="text" name="myinput" size=15>
<input type="button" onClick="checkMe()" value="check">
</form>
</body>
</html>
Looks like you want to use a regular expression. That's the most general (although sometimes also the most confusing) way to validate string data.
To check the input string you'd need something like this: (because you seem new to javascript I'll only give you hints to help you learn)
var user_input = prompt("Please enter the input string");
if (user_input == "123karthik");
alert('correct format');
else ...
I assume you can handle it on after the else!
NOTE: The code above is incomplete and is only for guidance.
![Interactive visualization of a graph in python [closed]](https://www.devze.com/res/2023/04-10/09/92d32fe8c0d22fb96bd6f6e8b7d1f457.gif)
加载中,请稍侯......
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