var num = 0; // 定义第一个输入的数据 function jsq(num) { //获取当前输入 if(num=="%"){ document.getElementById('screenName').value=Math.round(document.getElementById('screenName').value)/100; }else{ document.getElementById('screenName').value += document.getElementById(num).value; } } function eva() { //计算输入结果 document.getElementById("screenName").value = eval(document.getElementById("screenName").value); } function clearNum() { //清0 document.getElementById("screenName").value = null; document.getElementById("screenName").focus(); } function tuiGe() { //退格 var arr = document.getElementById("screenName"); arr.value = arr.value.substring(0,arr.value.length - 1); }