限制输入框只得输入数字(小数可以输入)

<script type="text/javascript" src="js/jquery-1.4.4.min.js"></script>

<script type="text/javascript">
$.fn.numeral = function() {
	$(this).css("ime-mode", "disabled");
	this.bind("keypress",function() {
		if (event.keyCode == 46) {
			if (this.value.indexOf(".") != -1) {
				return false;
			}
		} else {
			return event.keyCode >= 46 && event.keyCode <= 57;
		}
	});
	this.bind("blur", function() {
		if (this.value.lastIndexOf(".") == (this.value.length - 1)) {
			this.value = this.value.substr(0, this.value.length - 1);
		} else if (isNaN(this.value)) {
			this.value = "";
		}
	});
	this.bind("paste", function() {
		var s = clipboardData.getData('text');
		if (!/\D/.test(s));
		value = s.replace(/^0*/, '');
		return false;
	});
	this.bind("dragenter", function() {
		return false;
	});
	this.bind("keyup", function() {
	if (/(^0+)/.test(this.value)) {
		this.value = this.value.replace(/^0*/, '');
		} 
	});
};
</script>

<label>配额:</label>
<input type="text" id = "quota_setting" name="quota_setting" value="1.0"/>

<script type="text/javascript">
$("#quota_setting").numeral();
</script>