<!DOCTYPE html><html lang="en"><head> ???<meta charset="UTF-8"> ???<title>js判断字符串是否有下划线</title> ???????<script src="https://code.jquery.com/jquery-3.1.1.min.js"></script> ???</head><body> ???<!-- <input type="text" onclick="chk();"> --> ???<script> ???????var str="SH_20181030_3_25001"; ???????var a=str.length; ???????????????var str1 = str.replace(/\_+/g,"") ???????var b=str1.length; ???????var c=a-b; ???????if(c!==3){ ???????????//alert(‘名字下划线有问题‘); ???????}else{ ???????????//alert("ok"); ???????} ???????var a = /^\w{2}_\d{8}_\d{1,2}_\d{5}$/; ??????// alert(a.test(str)); ???????????????var aa="1"; ???????var b = /^\d{1,2}$/; ???????//alert(b.test(aa)); ???????// ???????// function chk() { ?// ??????????var patrn = /^\d+(\.\d+)?$/; ?// ??????????var result = true; ?// ??????????$("input[type=text]").each(function () { ?// ??????????????if (!patrn.exec(this.value)) { ?// ??????????????????alert("请输入正确的数字！"); ?// ??????????????????result = false; ?// ??????????????} ?// ??????????}) ?// ??????????return result; ?// ??????} ???</script> ????</body></html>js判断字符串是否有下划线
原文地址：https://www.cnblogs.com/quitpoison/p/10795474.html