console 命令行工具 X clear
console
<!DOCTYPE html>
<html>
<head>
 <meta charset="utf-8"/>
</head>
<body>
       <script>
var number1 = 22;
var number2 = 33;
var myString="Healther";

var sum = number1+number2;
document.write(sum+"<br/>");

var sum = number1+myString;
document.write(myString+'<br/>');

var sum = myString+number2;
document.write(myString+'<br/>');

var stringNum=number1+"";

var stringNumSum = stringNum+number2;
document.write(stringNumSum+'<br/>');


var left = 1;
var right = 2;

left += right;
document.write(left+"<br/");

left -=right;
document.write(left+"<br/");

left *= right;
document.write(left+"<br/");

left /= right;
document.write(left+"<br/");


left = ( 1 + 2 ) + 3;
right = ( 3 + 4 ) + 1;

document.write( (left > right )+"<br/>");
document.write( (left < right )+"<br/>");
document.write( (left >= right )+"<br/>");
document.write( (left <= right )+"<br/>");
document.write( (left == right )+"<br/>");
document.write( (left != right )+"<br/>");


var logicOperation = false;

logicOperation = (left > right) && ( left < right );
document.write(logicOperation + "<br/>");

logicOperation = true && (left < right);
document.write( logicOperation +"<br/>" );

logicOperation = (left > right)||(left < right);
document.write( logicOperation +"<br/>");

logicOperation = (left > right)|| false;
document.write(logicOperation +"<br/>");

logicOperation = !( left > right );
document.write(logicOperation +"<br/>");
logicOperation = !( left < right );
document.write(logicOperation +"<br/>");


document.write("Number('123')：" + Number("123") + "<br/>");
document.write("Number('3.1415')：" + Number("3.1415") + "<br/>");
document.write("Number('hao123')：" + Number("hao123") + "<br/>");
document.write("Number('100px')：" + Number("100px"));
    </script>
</body>
</html>