input character or number only using javascript

gistfile1.txt

##character Only
<input type="text" name="input_name" onkeypress='return ((event.charCode >= 65 && event.charCode <= 90) || (event.charCode >= 97 && event.charCode <= 122) || (event.charCode == 32))'>

##Number Only
<input type="text" onkeypress='return event.charCode >= 48 && event.charCode <= 57'>

##Check charCode
"+".charCodeAt()


<script>
    function isNumberKey(evt){
        var charCode = (evt.which) ? evt.which : evt.keyCode
        return !(charCode > 31 && (charCode < 48 || charCode > 57));
    }
    
    function alphaOnly(event) {
        var key = event.keyCode;
        return ((key >= 65 && key <= 90) || (event.keyCode > 96 && event.keyCode < 123) || key == 8);
    };
</script>