PostSparrow

Java script code

<input type="text" name="mobile_no" id="mobile_no" placeholder="Enter Mobile No" >
<script>
	$(document).ready(function(){
	    $("#mobile_no").keypress(function(e){
	        var keyCode = e.which;
	        /*
	          8 - (backspace)
	          32 - (space)
	          48-57 - (0-9)Numbers
	        */
	        if((keyCode != 8 || keyCode ==32 ) && (keyCode < 48 || keyCode > 57)) {
	            return false;
	        }
	        var name = $("#mobile_no").val();
	        if(name.length > 9){
	            return false;
	        }
	    });

	    $("#mobile_no").keyup(function(e){
	        var name = $("#mobile_no").val();
	        if(name.length > 0)
	        {
	            var key_arr = name.split("", 1);
	            if(key_arr[0] == 6 || key_arr[0] == 7 || key_arr[0] == 8 || key_arr[0] == 9)
	            {

	            }else{
	                $("#mobile_no").val('');
	            }
	        }
	    });
	});
</script>