一道课题求解
源代码函数缺少一部分，使函数查询输入域的每个字符并计算域中出现多少个字母e(提示：函数缺少的是for 循环)
<htmL><html><head><title></title><script type="text/javascript">function countE(form){ var count = 0; var inputString = form.mainstring.value.toLowerCase(); var msg = "The string has " + count; msg += " instances of the letter e." alert(msg);}</script></head><body><form>Enter any stirng:<input type="text" name="mainstring" size="30"><br/><input type="button" value="Conut the Es" onclick="countE(this.form)"></form></body></html></html>for(var i=0,len=inputString.length;i<len;i++){ if(inputString.charAt(i)=='e') count++;}