javascript simulation php function in_array_javascript tips

JS determines whether an element exists in a JS array, which is equivalent to the in_array function in the PHP language.

Array.prototype.S=String.fromCharCode(2); 
Array.prototype.in_array=function(e){ 
  var r=new RegExp(this.S+e+this.S); 
  return (r.test(this.S+this.join(this.S)+this.S)); 
}; 

Usage is as follows:

var arr=new Array(["b",2,"a",4,"test"]); 
arr.in_array('test');//判断 test 字符串是否存在于 arr 数组中，存在返回true 否则false，此处将返回true 

Note: This function is only valid for characters and numbers

There is a similar function in jQuery: http://docs.jquery.com/Utilities/jQuery.inArray

Its code is as follows:

function inArray(needle, haystack) {
  var length = haystack.length;
  for(var i = 0; i < length; i++) {
    if(haystack[i] == needle) return true;
  }
  return false;
}

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