实现代码:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head> <meta http-equiv="Content-Type" content="text/html;charset=UTF-8"> <title>Document</title> <style>*{margin: 0px;padding: 0px;}body{padding: 100px;}input[type=text]{width: 50px;background-color: #eee;border: 1px solid #ccc;height: 26px;line-height: 26px;}span{display: inline-block;width: 30px;}input[type=button]{padding: 5px 10px;} </style> <script>window.onload=function(){var aInput = document.getElementsByTagName('input');var oSpan = document.getElementsByTagName('span')[0];var oBtn = document.getElementById('btn');for(var i=0;i<aInput.length-1;i++){aInput[i].onkeyup=function(){this.value = this.value.replace(/[^\d]/,'')}}oBtn.onclick=function(){(aInput[0].value==""||aInput[1].value=="")?alert('请输入数字'):oSpan.innerHTML=parseInt(aInput[0].value)+parseInt(aInput[1].value);}} </script> </head> <body><input type="text" />+ <input type="text" />= <span></span><input id="btn" type="button" value="求和" /> </body> </html>
这里有用到正则表达式判断输入是否为数字。
结果如下图所示: