JavaScript10以内加法在线测试练习

+=

function calculate(){

document.getElementById("result").value="";

document.getElementById("message").innerHTML="";

var left = document.getElementById("left").value;

var right = document.getElementById("right").value;

var p = new RegExp("^(-?\\d+)(\\.\\d+)?$");

varisleftnumber = p.test(left);

varisrightnumber = p.test(right);

if(!isleftnumber){

document.getElementById("message").innerHTML="请在左值处输入数字";

return;}

document.getElementById("message").innerHTML="";

if(!isrightnumber){

document.getElementById("message").innerHTML="请在右值处输入数字";

return;}

document.getElementById("message").innerHTML="";

if(isleftnumber&&isrightnumber){

document.getElementById("result").value=parseFloat(left)+parseFloat(right);}

}

左值：

右值：

结果：