想要实现限定文本框内只能输入15位的数字的效果。但是现在实现的情况是只能限定不能输入英文字母，还不能限制汉字的输入，从网上找到的资料看来，需使用正则表达式来判断。不建议使用依赖keycode的判断，因为粘贴、中文输入法、自动填表等都是不触发key事件的。
而且限定的length是15，却能输入17位数字
<!DOCTYPE html> <html> <head lang="en"> <meta charset="UTF-8"> <title>限制用户只能输入数字</title> <link href="../../css/main.css" rel="stylesheet" type="text/css"/> <link href="../../css/rawJavascript.css" rel="stylesheet" type="text/css"/> <script src="../../js/util.js"></script> </head> <body> <div class="content-box numOnly"> <form id="form1"> <div class="list-item"> <label for="numOnly">限定只能输入15位数字</label><input id="numOnly" type="text"/><span class="delete fl" title="清除" >×</span> <span id="info" class="info"></span> </div> </form> </div> <script> var str = ''; window.onload = function () { var form1 = document.getElementById('form1'); var numOnly = document.getElementById('numOnly'); var delBtn = getByClass(form1,'delete'); numOnly.onkeydown = function (ev) { var oEvent = ev||event; if(str.length<=15){ if((oEvent.keyCode>=48)&& (oEvent.keyCode<=57)||((oEvent.keyCode>=96)&&(oEvent.keyCode<=105))||(oEvent.keyCode==8)){ str = numOnly.value; if(str.length>0){ showDel(delBtn[0],numOnly); }else{ disDel(delBtn[0]); } }else{ info.innerHTML = "只能输入15位"; return false; }; } else{ return false; } }; numOnly.onfocus = function () { if(str.length>0){ showDel(delBtn[0],numOnly); }; }; numOnly.onblur = function () { disDel(delBtn[0]); } }; function showDel(obj, functor ) { obj.style.display = "block"; obj.onclick = function () { functor.value = ""; str = ''; }; }; function disDel(obj) { obj.style.display = "none"; }; </script> </body> </html>
css样式
.numOnly { position: relative; } .list-item{ position: relative; display: inline; } .list-item input{ padding-right: 20px; letter-spacing: 2px; } .list-item .info{ display: block; color: #eb4960; } .numOnly .delete{ position: absolute; right: 1px; margin-top: -22px; padding: 0px 5px; cursor: pointer; display: none; } .numOnly .delete:hover{ background: #eeeeee; }
-------------找到正确的实现方法时会补充---2016-06-29-----------------------------------------