用javascript编写网页：实现加减乘除的计算器

将实现加减乘除的函数存放在2.js:

// 2.js

function f1(){
	var sum=0;
	var s1=document.forms[0].text_1.value;
	var s2=document.forms[0].text_2.value;
	sum=Number(s1)+Number(s2);
	document.forms[0].text_3.value=sum;
}
function f2(){
	var sum=0;
	var s1=document.forms[0].text_1.value;
	var s2=document.forms[0].text_2.value;
	sum=Number(s1)-Number(s2);
	document.forms[0].text_3.value=sum;
}

function f3(){
	var sum=0;
	var s1=document.forms[0].text_1.value;
	var s2=document.forms[0].text_2.value;
	sum=Number(s1)*Number(s2);
	document.forms[0].text_3.value=sum;
}

function f4(){
	var sum=0;
	var s1=document.forms[0].text_1.value;
	var s2=document.forms[0].text_2.value;
	sum=Number(s1)/Number(s2);
	document.forms[0].text_3.value=sum;
}

将主程序放在2.html:

// 2.html

function f1(){
    
    
	var sum=0;
	var s1=document.forms[0].text_1.value;
	var s2=document.forms[0].text_2.value;
	sum=Number(s1)+Number(s2);
	document.forms[0].text_3.value=sum;
}
function f2(){
    
    
	var sum=0;
	var s1=document.forms[0].text_1.value;
	var s2=document.forms[0].text_2.value;
	sum=Number(s1)-Number(s2);
	document.forms[0].text_3.value=sum;
}

function f3(){
    
    
	var sum=0;
	var s1=document.forms[0].text_1.value;
	var s2=document.forms[0].text_2.value;
	sum=Number(s1)*Number(s2);
	document.forms[0].text_3.value=sum;
}

function f4(){
    
    
	var sum=0;
	var s1=document.forms[0].text_1.value;
	var s2=document.forms[0].text_2.value;
	sum=Number(s1)/Number(s2);
	document.forms[0].text_3.value=sum;
}

运行结果：