The isFinite() method is used to determine if a variable has finite bounds.
<html> <body> <script lanuguage="JavaScript"> <!-- function checkNum(){ var n = document.form1.text1.value; if(isFinite(n) == true){ alert("Your entry had finite bounds"); }else{ alert("Your entry had no finite bounds"); } } -->
</script> <form name="form1"> Enter a number or character into the text box and then click the check value button to verify if the input is a number. <br><br> <input type="text" name="text1" size=3> <br><br> <input type="button" value="Check value" onClick='checkNum()'> <br> </form> </body> </html>
