1.input
<input type="text" onkeyup="filterNum(this)" onpaste="filterNum(this)" required lay-verify="required" placeholder="请输入3至30个字符" autocomplete="off" class="layui-input">
2.js
function filterNum(obj) {
obj.value = obj.value.replace(/[^\d.]/g, "");
obj.value = obj.value.replace(/\.{2,}/g, ".");
obj.value = obj.value.replace(".", "$#$").replace(/\./g, "").replace("$#$", ".");
obj.value = obj.value.replace(/^(\-)*(\d+)\.(\d\d).*$/, '$1$2.$3');
if (obj.value.indexOf(".") < 0 && obj.value != "") {
obj.value = parseFloat(obj.value);
}
}