<!DOCTYPE html><html> <head> <title> 事件</title> <script type="text/javascript"> function count(){ var one=parseInt(document.getElemenById("text1").value); //获取第一个输入框的值 var two=parseInt(document.getElemenById("text2").value); //获取第二个输入框的值 var three=document.getElemenById("select").value; var result=""; //获取选择框的值 switch(three){ care "+"; result = parseFloat(one) + parseFloat(two); break; care "-"; result = parseFloat(one) - parseFloat(two); break; care "*"; result = parseFloat(one) * parseFloat(two); break; care "/"; result = parseFloat(one) / parseFloat(two); break; } document.getElementById("fruit").value = result; } //获取通过下拉框来选择的值来改变加减乘除的运算法则 //设置结果输入框的值 } </script> </head> <body> <input type='text' id='txt1' /> <select id='select'> <option value='+'>+</option> <option value="-">-</option> <option value="*">*</option> <option value="/">/</option> </select> <input type='text' id='txt2' /> <input type='button' value=' = ' onclick=count() /> <!--通过 = 按钮来调用创建的函数，得到结果--> <input type='text' id='fruit' /> </body></html>
