正则表达式检查第一个字符是否为大写，并且仅允许字母数字，不允许特殊字符。 谢谢提前

    function checkName(val) {     
    var alpha = document.getElementById(val).value;     
    var filter = /^[a-zA-Z0-9 ]*$/;     
    if (!filter.test(alpha)) { 
        alert("Please Enter Alphanumeric Only"); 
        return false;                                                    
    }  
    return true;    
  }   

i Used This its working properly for checking alphanumeric but for first character uppercase its not working where can i modify my regex expression or any solution.

请您参考如下方法:

尝试

/^[A-Z][a-zA-Z0-9]+/ 

例如

/^[A-Z][a-zA-Z0-9]+/.test("Asd");