jQuery 检查字符串中的空格

Check Space in String

提问by Azam Alvi

I want to check that if my username contains space so then it alert so i do this it work but one problem i am facing is that if i give space in start then it does not alert.I search it but can't find solution, my code is this

我想检查我的用户名是否包含空格，然后它会发出警报，所以我这样做它可以工作，但我面临的一个问题是，如果我在开始时提供空间，则它不会发出警报。我搜索它但找不到解决方案，我的代码是这样的

var username    =   $.trim($('#r_uname').val());
var space = " ";
  var check = function(string){
   for(i = 0; i < space.length;i++){
     if(string.indexOf(space[i]) > -1){
         return true
      }
   }
   return false;
  }

  if(check(username) == true)
  {
     alert('Username contains illegal characters or Space!');
     return false;
  }

回答by Blender

Just use .indexOf():

只需使用.indexOf()：

var check = function(string) {
    return string.indexOf(' ') === -1;
};

You could also use regex to restrict the username to a particular format:

您还可以使用正则表达式将用户名限制为特定格式：

var check = function(string) {
    return /^[a-z0-9_]+$/i.test(string)
};

回答by doublesharp

You should use a regular expression to check for a whitespace character with \s:

您应该使用正则表达式来检查空格字符\s：

if (username.match(/\s/g)){
    alert('There is a space!');
}

See the code in action in this jsFiddle.

请参阅此jsFiddle中的操作代码。

回答by Javid Dadashkarimi

why you don't use something like this?

你为什么不使用这样的东西？

if(string.indexOf(space) > -1){
     return true
  }