js实现文本框支持加减运算的方法
<!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">
<head>
<title>支持加减运算的文本框</title>
<meta http-equiv="content-type" content="text/html;charset=gb2312">
<style type="text/css">
body{color:#000;font-size:14px;font-family:Verdana,Arial,Helvetica,sans-serif,"宋体";}
input{border-style:solid;border-color:#868275;background-color:#f9f9f9;border-width:1px;color:#505050;vertical-align:middle;}
</style>
<script language=javascript>
function FloatAdd(arg1,arg2){
var r1,r2,m;
try{r1=arg1.toString().split(".")[1].length}catch(e){r1=0}
try{r2=arg2.toString().split(".")[1].length}catch(e){r2=0}
m=Math.pow(10,Math.max(r1,r2))
return (arg1*m+arg2*m)/m
}
function FloatSubtr(arg1,arg2){
return FloatAdd(arg1,-arg2);
}
function IsMoney(Money){
if(/^[\d|+|.|-]+$/.test(Money)) return true;
return false;
}
function result(){
str=document.getElementById("buy").value;
if(!(IsMoney(str))){
document.getElementById("amount").innerHTML ="无效金额";
return false;
}
var len=str.length,money=0,Num=0;
var NumStr="",ctrlflag="x",cflag=0;
for(var i=0;i<len; i++){
c= str.charAt(i);
if((c=="+")||(c=="-")){
if(i+1<len){
if ((str.charAt(i+1)=="+")||(str.charAt(i+1)=="-")) continue;
}
if((NumStr!="")&&(isNaN(NumStr))){
if(isNaN(NumStr)){
document.getElementById("amount").innerHTML ="输入无效金额";
return false;
}
}
if(NumStr!=""){
//alert("i："+i+"NumStr:"+NumStr);
if ((ctrlflag=="+")||(ctrlflag=="x")){
Num=parseFloat(NumStr);
//alert(ctrlflag+"money："+money+"Num："+Num);
money=FloatAdd(money,Num);
NumStr="";
Num=0;
ctrlflag=c;
}
else{
//alert(money+"里面减了"+NumStr);
Num=parseFloat(NumStr);
money=FloatSubtr(money,Num);
NumStr="";
Num=0;
ctrlflag=c;
}
}
else{
ctrlflag=c;
}
continue;
}
else{
NumStr=NumStr+""+c;
}
}
if((NumStr!="")&&(isNaN(NumStr))){
if (isNaN(NumStr)){
document.getElementById("amount").innerHTML ="无效金额"+NumStr;
return false;
}
}
if((ctrlflag=="-")&&(NumStr!="")){
Num=parseFloat(NumStr);
money=FloatSubtr(money,Num);
}
if(((ctrlflag=="+")||(ctrlflag=="x"))&&((NumStr!=""))){
Num=parseFloat(NumStr);
money=FloatAdd(money,Num);
}
document.getElementById("amount").innerHTML =money;
}
</script>
</head>
<body>
请输入加减计算式：<input id="buy" name="buy" maxlength="30" type="text" onkeyup="javascript:result();">
<span id="amount"></span>
</body>
</html>
<!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">
<head>
<title>支持加减运算的文本框</title>
<meta http-equiv="content-type" content="text/html;charset=gb2312">
<style type="text/css">
body{color:#000;font-size:14px;font-family:Verdana,Arial,Helvetica,sans-serif,"宋体";}
input{border-style:solid;border-color:#868275;background-color:#f9f9f9;border-width:1px;color:#505050;vertical-align:middle;}
</style>
<script language=javascript>
function FloatAdd(arg1,arg2){
var r1,r2,m;
try{r1=arg1.toString().split(".")[1].length}catch(e){r1=0}
try{r2=arg2.toString().split(".")[1].length}catch(e){r2=0}
m=Math.pow(10,Math.max(r1,r2))
return (arg1*m+arg2*m)/m
}
function FloatSubtr(arg1,arg2){
return FloatAdd(arg1,-arg2);
}
function IsMoney(Money){
if(/^[\d|+|.|-]+$/.test(Money)) return true;
return false;
}
function result(){
str=document.getElementById("buy").value;
if(!(IsMoney(str))){
document.getElementById("amount").innerHTML ="无效金额";
return false;
}
var len=str.length,money=0,Num=0;
var NumStr="",ctrlflag="x",cflag=0;
for(var i=0;i<len; i++){
c= str.charAt(i);
if((c=="+")||(c=="-")){
if(i+1<len){
if ((str.charAt(i+1)=="+")||(str.charAt(i+1)=="-")) continue;
}
if((NumStr!="")&&(isNaN(NumStr))){
if(isNaN(NumStr)){
document.getElementById("amount").innerHTML ="输入无效金额";
return false;
}
}
if(NumStr!=""){
//alert("i："+i+"NumStr:"+NumStr);
if ((ctrlflag=="+")||(ctrlflag=="x")){
Num=parseFloat(NumStr);
//alert(ctrlflag+"money："+money+"Num："+Num);
money=FloatAdd(money,Num);
NumStr="";
Num=0;
ctrlflag=c;
}
else{
//alert(money+"里面减了"+NumStr);
Num=parseFloat(NumStr);
money=FloatSubtr(money,Num);
NumStr="";
Num=0;
ctrlflag=c;
}
}
else{
ctrlflag=c;
}
continue;
}
else{
NumStr=NumStr+""+c;
}
}
if((NumStr!="")&&(isNaN(NumStr))){
if (isNaN(NumStr)){
document.getElementById("amount").innerHTML ="无效金额"+NumStr;
return false;
}
}
if((ctrlflag=="-")&&(NumStr!="")){
Num=parseFloat(NumStr);
money=FloatSubtr(money,Num);
}
if(((ctrlflag=="+")||(ctrlflag=="x"))&&((NumStr!=""))){
Num=parseFloat(NumStr);
money=FloatAdd(money,Num);
}
document.getElementById("amount").innerHTML =money;
}
</script>
</head>
<body>
请输入加减计算式：<input id="buy" name="buy" maxlength="30" type="text" onkeyup="javascript:result();">
<span id="amount"></span>
</body>
</html>
